Names and formulae of carbon compounds - National STEM Centre

Chemistry
Names and formulae
of carbon compounds
a programmed
text
14 082661 0
Nuffield Advanced Science
1111~I~i~II~~~ l~llm
N12566

Project team
E. H. Coulson, formerly of County High School, Braintree (organizer)
A. W- B. Aylmer-Kelly, formerly of Royal Grammar School, Worcester
Dr E. Glynn, formerly of Croydon Technical College
H. R. Jones, formerly of Carlett Park College of Further Education
A. J. Malpas, formerly of Highgate School
Dr A. L. Mansell, formerly of Hatfield College of Technology
J. C. Mathews, King Edward VII School, Lytham
Dr G. Van Praagh, formerly of Christ's Hospital
J. G. Raitt, formerly of Department of Education, University of Cambridge
B. J. Stokes, King's College School, Wimbledon
R. Tremlett, College of St Mark and St John
M. D. W. Vokins, Clifton College
Author of this book Dr Erica Glynn

Chemistry
Names and formulae
of carbon compounds
a programmed
text
Nuffield Advanced Science
Published for the Nuffield Foundation by Penguin Books

Penguin Books Ltd, Harmondsworth, Middlesex, England
Penguin Books Inc., 7110 Ambassador Road, Baltimore, Md 21207, U.S.A.
Penguin Books Ltd, Ringwood, Victoria, Australia
Copyright © The Nuffield Foundation, 1971
Filmset in 10 on 12pt 'Monophoto' Times by
Oliver Burridge Filmsetting Ltd, Crawley, Sussex,
and made and printed in Great Britain by
Design and art direction by Ivan and Robin Dodd
Illustrations designed and produced by Penguin Education
This book is sold subject to the condition that it shall not, by way of trade or
otherwise, be lent, re-sold, hired out, or otherwise circulated without the
publisher's prior consent in any form of binding or cover other than that in
which it is published and without a similar condition including this condition
being imposed on the subsequent purchaser

v
Contents
Foreword
ix
Introduction
xi
Notes for students
xiii
Part one
The main programme
Chapter 1
Programmed sections
Section A
Introduction (AI) 3
Molecular and· structural formulae (AI-A4) 4
Structural formulae and molecular geometry (A5-A6) 9
Summary (A7) 11
Section B
IUPAC systematic nomenclature (Bl) 12
Alkanes and halogenoalkanes (B2-B4) 13
Structural isomers - chloropropanes (B5- B8) 15
Isomeric dichloropropanes (B9- B13) 18
Structural formulae deduced from systematic names - isomeric
dichloroethanes (B14-B17) 22
Formula of 1,1,2-trifluorobutane (B18-B19) 24
IUPAC names of alkanes (B20) 27
Halogenoalkanes containing more than one halogen (B21) 28
Condensed structural formulae (B22) 30
Summary (B23) 30
Section C
Functional groups and systematic names (Cl) 33
IUPAC names of alcohols (C2) 34
Alcohols containing two or more hydroxyl groups (C3-C6) 36
Alkenes (C7) 39
IUPAC names ofalkenes (C8) 41
Isomeric alkenes (C8-CIO) 42

vi
IUPAC names and structural formulae ofdienes (CII-CI5) 44
Cyclic carbon compounds (CI6) 48
IUPAC names and structural formulae of cycloalkanes, etc.
(CI6-CI8) 49
Isomers of butane and pentane (CI9) 52
Branched chain alkanes (C20) 53
IUPAC names of branched chain alkanes (C21-C22) 54
Structural formula of 2,2,4-trimethylpentane (C23-C24) 56
Branched chloroalkanes and alcohols (C2S) 57
General information provided by systematic names (C26) 60
Examples of additional rules (C27) 60
Summary (C28) 62
Section D
Alkynes (D 1) 65
Names ofalkynes (DI) 66
Benzene (D2) 66
Systematic names of benzene derivatives (D2-D4) 66
Trivial names of benzene derivatives (D5-D6) 71
Aldehydes, carboxylic acids, and acid chlorides (D7 - D 12) 74
Substituted carboxylic acids and aldehydes (D13-DI4) 80
Condensed formulae (D 15) 82
Summary (DI6) 84
Chapter 2
Review problems
2.1 Review of Section B 87
2.2 Review of Section C 90
2.3 Optional problems, Section C 91
2.4 Review of Sections B to D 92
2.5 Further optional problems 94
Part two
Optional work and answers to review problems
Chapter 3
Optional exercises
3.1 Addi tional exercises for Section A 99
3.2 Additional exercises for Section B 102
3.3 Additional exercises for Section C 108
3.4 Additional exercises for Section D 112

Chapter 4
Review and extension information
4.1 Structural formulae 119
a Interpretation of structural formulae 119
b Formula of benzene 120
c Condensed and expanded structural formulae 122
4.2 Structural isomers 125
4.3 Primary, secondary, and tertiary ca'rbon atoms 128
4.4 Numbering of carbon atoms 130
4.5 Saturated and unsaturated compounds 132
a Types of reactions 132
b Names of saturated and unsaturated compounds 134
4.6 Names of (a) alkanes, (b) alkyl groups, and (c) other groups 135
a Alkanes containing an unbranched chain of carbon atoms 135
b Alkyl groups 135
c Other groups 137
4.7 Functional groups 138
a Functional groups containing only carbon atoms 138
b Functional groups containing only atoms other than carbon 139
c Functional groups containing carbon as well as other elements 140
4.8 Names of carbon compounds 142
a Compounds in Chapter I 142
b Aldehydes 142
c Ketones 143
d Carboxylic acids and derivatives 144
e Ethers 145
f Cyanides 145
gAmines and ammonium salts 145
h Derivatives of benzene 147
Compounds with more than one functional group 149
4.9 American usage of systematic nomenclature 149
4.10 Trivial and other names 150
a Names of series of compounds 150
b Hydrocarbons 150
c Halogenoalkanes 150
d Alcohols 151
e Aldehydes 151
f Ketones 151
g Carboxylic acids 151
h Derivatives of carboxylic acids 151
Ethers and cyanides (nitriles) 152
Derivatives of benzene 152
vii

viii
Chapter 5
Answers to review problems, Chapter 2
5.1 Answers to 2.1 153
5.2 Answers to 2.2 155
5.3 Answers to 2.3 157
5.4 Answers to 5.4 159
5.5 Answers to 5.5 161
Notes for teachers 165

ix
Foreword
It is almost a decade since the Trustees of the Nuffield Foundation decided to
sponsor curriculum development programmes in science. Over the past few
years a succession of materials and aids appropriate to teaching and learning
over a wide variety of age and ability ranges has been published. We hope
that they may have made a small contribution to the renewal of the science
curriculum which is currently so evident in the schools. The strength of the
development has unquestionably lain in the most valued part that has been
played in the work by practising teachers and the guidance and help that has
been received from the consultative committees to each Project.
The stage has now been reached for the publication of materials suitable for
advanced courses in the sciences. In many ways the task has been a more
difficult one to accomplish. The sixth form has received more than its fair
share of study in recent years and there is now an increasing acceptance that
an attempt should be made to preserve breadth in studies in the 16 to 19 year
age range. This is no easy task in a system which by virtue of its pattern of
tertiary education requires standards for the sixth form which in many other
countries might well be found in first year university courses.
Advanced courses are therefore at once both a difficult and an interesting
venture. They have been designed to be of value to teacher and student, be
they in sixth forms or other forms of education in a similar age range.
Furthermore, it is expected that teachers in universities, polytechnics, and
colleges of education may find some of the ideas of value in their own work.
If these advanced courses meet with the success and appreciation I believe
they.deserve, it will be in no small measure due to a very large number of
people in the team so ably led by Ernest Coulson, in the consultative
committee, and in the schools in which trials have been held. The programme
could not have been brought to a successful conclusion without their help
and that of the examination boards, local authorities, the universities, and
the professional associations of science teachers. Finally, the Project materials
could not have reached successful publication without the expert assistance
that has been received from William Anderson and his editorial staff in the
Nuffield Science Publications Unit and from the editorial and production
teams of Penguin Education.
K. W. Keohane
Co-ordinator of the Nuffield Foundation Science Teaching Project

xi
Introduction
This book is one of four programmed texts written for the Nuffield Advanced
Chemistry course. This course, up-to-date in content and experimental in basis,
is intended for the 16 to 18year age range and to lead to the Advanced Level
examination of the GCE. The programmed texts were developed in close
collaboration with teachers and students in the Chemistry Trials Schools.
Successful integration into school courses and relevance to actual classroom
situations were the main aims throughout the writing, development, and
evaluation of these programmes. They are designed for use during the first year
of the Advanced Chemistry course, or for revision.
This programme, Names andformulae of carbon compounds, can be used as an
aid to introducing organic chemistry, either as preliminary work before starting
Topic 9, or during the early stages of this topic. Parts of the programme, for
instance the optional sections in Part two, are useful background work
throughout Topics 9 and 13.
A major difficulty for students starting a study of carbon compounds is the
wide range of formulae, functional groups, systematic and other names, which
they must learn to use and interpret. Evaluation of this programme has shown
that it not only helped students to overcome these initial difficulties, but the
information of scientific and technological interest included in the programme
also gave students some insight into important aspects of modern organic
chemistry. In general the programme made subsequent study of the subject
easier.
The programme has been constructed in such a way as to allow for maximum
flexibility in use. 'Notes for teachers', at the end of this book, explain this in
greater detail. Further information about the use of programmed learning
in the course can be found in Appendix 6 of Teachers' Guide II.
Particular appreciation of the invaluable help of teachers in the Chemistry
Trials Schools must be expressed; they coped valiantly with the task of
programme evaluation during the busy period involving the trials of the main
project. The help and advice of Dr Peter Sykes and of teachers in a variety of
institutions is also gratefully acknowledged.

xiii
Notes for students
Compounds of carbon are the main constituents of all living matter, of new
pharmaceuticals such as antibiotics, of fuels, plastics, fibres, and other materials
of special interest. Since millions of carbon compounds are known, it has been
essential to devise an internationally accepted system of naming them in such
a way that the structural formula of a compound can be deduced from its
systematic name.
This programmed text will help you to use and interpret the names and formulae
of carbon compounds, which form the vast majority of all known chemical
compounds. It also includes general information about the use and
importance of some of these compounds; this information, given in smaller
type, is optional, and you are not expected to learn it at this stage.
You will find that Sections A to D of Part one, The main programme, have been
divided into a number of subsections and that you are directed to read a
particular subsection: •»»>-+ A2', for instance, means 'read subsection A2 next'.
Most of these subsections contain questions which are not tests but are designed
to help you understand the material more thoroughly. Answers to these
questions are usually given below, or at the foot of the facing righthand page,
but you should do your best to see how far you can deal with each question
yourself, before looking at the answer. It is suggested that you write down your
answers on separate sheets of paper, particularly answers which involve actual
names or formulae, so that you can check these precisely. Suitable stages to
interrupt your work, if you are ·unable to proceed to the end of a particular
section, are indicated by a thick solid line across the page. A summary, with
references to relevant subsections, is given at the end of each Section, A to D.
Chapter 2 contains Review problems the answers to which are given in Chapter 5.
These will help you to assess how well you have understood and can apply the
ideas given in Chapter 1.
Chapter 3 of Part two contains Optional exercises, which you can work through
for extra practice. The purpose of the Review and extension information in
Chapter 4 is to provide opportunities for extending your knowledge, and in
particular to apply this to a wider range of compounds. Cross references are
given throughout to help you identify related points.

xiv
If you are using this book for revision, you may prefer not to work through the
whole of Chapter I in the first instance, but to read in turn each of the
summaries of Sections A to D in this chapter, and to attempt the corresponding
Review problems in Chapter 2. This will help you to decide whether you need
to work through any particular section, or alternatively through the Optional
exercises in Chapter 3.
At present, non-systematic names are still used for a number of compounds,
especially in older books. Examples of commonly used names of this type are
given in Chapter 1; a more comprehensive list can be found in Chapter 4,
section 4.10.

Part one
The main programme

3
Chapter 1
Programmed sections
Section A
Introduction
All living matter is primarily made up of compounds of carbon. The
chemistry of carbon compounds was therefore originally referred to as
organic chemistry and this term is still widely used.
Vast numbers of organic compounds are known, and new ones are being
isolated from natural sources and prepared in the laboratory at a
rapidly increasing rate (figure 1). During the course of his career a
research chemist might prepare hundreds of new carbon compounds.
Some of these may prove to be of great economic value, for instance
new plastics, fibres, or pharmaceutical chemicals.
A1
1000 000
500 000
1900 1920 1940 1960
Figure 1
Number of known organic compounds, 1900-60.
After Richards, J. H., Cram, D. J., and Hammond, G. S. (1967) Elements of organic
chemistry, McGraw-Hill
Date

4 Programmed sections
Petroleum is one of the most important sources of organic materials. It has been estimated
that petroleum constituents which boil below 200°C consist of at least five hundred
different compounds.
Note
Small type in this chapter is used for (1) tables, and (2) as above for
matter of general information.
Molecular and structural formulae
Formulae are widely used in communicating information about
chemical compounds. In some cases, the molecular formula, which shows
the actual number of atoms of each element present in one molecule of
the compound is adequate. C 2 H 6 , for instance, corresponds to only one
compound, ethane. Figure 2 shows three different molecular models, all
of which represent ethane.
H
H
H·
H H
I I
H-C-C-H
I I
H H
Figure 2
Ethane: (a) ball-and-spoke model, (b) skeletal and space-filling models, (c) structural
formula.
A particular molecular formula frequently represents more than one
compound. C 9 H 20 is the molecular formula of thirty-five compounds,
which have different structural formulae. In such cases structural
formulae, which show how constituent atoms are bonded to each other,
must be used (see figure 2 for structural formula of ethane).
b

Programmed sections
5
By 1947all compounds of molecular formulae C 9 H 20 and over half of
the seventy-five possible C 1o H 22 compounds were known. A simple
example, C S H 12 , is discussed in A2.
~ A2 (Read A2 next.)
Three different compounds with molecular formula C S H 12 are known.
They differ in properties such as boiling point and have different
structural formulae. Two of these compounds are shown below and on
page 6. (The third compound is given in A4. Read this ifyoll wish.)
Compound A-boiling point 28°C
A2
Molecular formula C S H 12
H
I
H-C-H
Y I y y
Structural formula H - C- C- C- C- H
I [ I I
H H H H
CH 3
I
Condensed structural formula CH 3 -CH-CH 2 -CH 3
Figure 3a
Compound A.

6 Programmed sections
Compound B - boiling point 36°C
Molecular formula CsH 12
H H H H H
I I I I I
Structural formula H - C- C- C- C- C- H
1 I I I I
H H H H H
Figure3b
Compound B.
Note
The illustrations of the models of A and B and their structural formulae
will help you to answer the question given below. Construct your own
models, if these are available.
Uuestion
Which of the following statements are correct?
1 Structural formulae show which atoms are bonded to each other, and
the types of bonds (single, double, etc.) present.
2 The five carbon atoms in compound B (figure 3b) are arranged in a
straight line.

Programmed
sections
7
3 Structural formulae do not indicate directly geometric features present
in a molecule.
~ A3 if you need help; otherwise A5 after checking your answer which is
given below.
Optional
a Examine the structural formulae of compounds A and B in A2. This
should help you to decide whether statement 1 is correct.
b Look at the photograph of the model of compound B in figure 3b. This
shows the arrangement in space of the atoms in a molecule of B. Is
statement 2 correct?
c Does CH3-CHz-CHz-CHz-CH3 (condensed structural formula
of B) indicate directly geometric features such as the arrangement of
atoms in space?
Attempt the question in A2.
A3
Answer to A2
Statements 1 and 3 are correct. 2 is incorrect.
Note
The atoms in the carbon chain of compound B are not arranged in a
straight line (see illustration of model). Structural formulae such as
CH3- CHz- CHz- CH 2 - CH3 do not depict the actual geometric
arrangement of the various atoms.
~ Read A2 and A3 .again if you had any difficulties; otherwise A5.

8 Programmed sections
Optional
A third compound, C, of molecular formula C S H 12
A4
is known (see A2).
Compound C - boiling point 9 °c
Molecular formula' C S H 12
H
I
H-C-H
~ I ~
Structural formula H - C- C- C- H
~ I ~
H-C-H
I
Condensed structural formula
H
CH 3
I
CH-C-CH
3 I 3
CH 3
Figure 4
CompoundC.
~ A2 (page 5)

Programmed sections 9
Structural formulae and molecular geometry
Structural formulae are useful but need careful interpretation from the
point of view of molecular geometry. This is illustrated in figure 5, and
in the question on the next page.
AS
Recent research has led to an increasing awareness of the influence of geometric factors on
the physical and chemical properties of materials. An article, which discussed the award
of the 1969Nobel Prize in chemistry for work in this field to Professor D. H. R. Barton
of London and Professor O. Hassel of Oslo, included the following comment:
'... no one can seriously examine the course of any chemical reaction without considering
the detailed geometric changes involved.' (Chemistry in Britain (1969), 5, 12, p. 570).
Most organic melecules are flexible and alter their shape by rotation
about single bonds. The carbon chain in compound B,
CH3-CH2-CH2-CH2-CH3, can adopt a number of rotational
positions, as shown in figure 5.
'; (
" \~~
-rotation of
carbon atom
on the right
Figure 5
Three rotational positions of a chain of five carbon atoms.
rotation - of
carbon atom
on the left
If 'ball-and-spring' or other types of models are available, construct a
model of compound B and note the changes in shape brought about by
rotational movements.

10 Programmed sections
Uuestion
The structural formulae P, Q, and R (see below) represent:
A the same compound,
B two different compounds,
c three different compounds.
Which statement is correct: A, B, or c?
CH3-CH2-CH2-CH2-CH3
p
CH -CH
--CH
I 2 2 I 2
CH3 CH 3
Q
CH 3
I
CH2-CH2-CH2
I
CH 3
R
»»)-+ A6 if you need help with the above question; otherwise A7 after checking
your answer (opposite).
Optional
Look at figure 5 in A5 again, and note how a chain in which carbon
atoms are linked by single bonds can alter its shape due to rotation.
Remember also that structural formulae do not convey an actual
picture of the arrangement of different atoms in space.
Attempt the question in A5.
A6

Programmed
sections
11
Summary
1 Well over a million compounds of carbon (organic compounds) are
known. A particular molecular formula frequently represents more
than one organic compound. (The molecular formula shows the actual
number of atoms of each element present in one molecule of the
compound.) Structural formulae, which show which atoms are bonded
to each other and the types of bonds present, must be used in most cases
(see Al and 4.la, Chapter 4).
2 Three different compounds have the same molecular formula C S H12.
Their structural formulae can be written out fully, or simplified
(condensed) for.mulae can be used (see A2 and A4).
3 Structural formulae do not give any details of geometric features of
molecules such as the arrangement of atoms in space (see A2 and A3).
4 Most organic molecules are flexible and can alter their shape by rotation
about single bonds. A given structural formula can often be written in
more than one way (see question on page 10).
The simplest way ( in this case) is generally preferred (see AS and A6).
Note
1. Further optional exercises relating to structural formulae of simple
carbon compounds are given in section 3.1 of Chapter 3. Work through
these if you feel you need this additional practice.
2. Structural formulae are discussed further in Chapter 4,4.1.
A7
Answer to A5
The structural formulae represent the same compound; A is correct.
Note
~ A7
P, Q, and R represent compound B (see A2 and AS). The structural
formula can be written in a number of different ways; the preferred way
is P, CH3-CH2-CH2-CH2-CH3'

12 Programmed sections
Section B
IUPAC systematic nomenclature
Organic chemists use structural formulae extensively since, as outlined
in Section A, these formulae show the chemical bonds present in a
compound. It is often more convenient to use the name of a compound
rather than the formula.
»)))00-+ B 2
In the past compounds were generally given 'trivial' or 'common' names based on their
source, for instance, vanillin (from vanilla pod), cadaverine, and putrescine (both present
in decaying animal material). This sometimes led to more than one name for a particular
compound: caffeine (present in coffee and tea) was originally also called theine. These
trivial names had no direct relation to the structure of the compounds, which in any case
had often not been determined. The enormous number of organic compounds now known
(see AI) makes it impossible to remember the trivial names of more than a few, and a
systematic method for naming them has had to be devised. Non-systematic names are still
used to some extent especially for important complex compounds such as penicillin.
(Examples of non-systematic names are given in Chapter 4, 4.10.)
Chemists need an internationally accepted system of naming compounds
in such a way that the name can be translated unambiguously into a
structural formula. Such a system, which enables us to deduce the
precise structural formula of a compound from its name, has been
devised by the International Union of Pure and Applied Chemistry
(IUPAC systematic nomenclature).
Some of the more important IUP AC rules for naming carbon
compounds are given in this text. Once you are familiar with these, you
will not find it difficult to apply further rules as you meet new
compounds. (Some of these additional rules are given in optional
sections of Chapter 4, particularly 4.8.)
B1

Programmed sections
13
82
Alkanes and halogenoalkanes
Compounds which contain carbon and hydrogen only are called
hydrocarbons. Alkanes are one important class of hydrocarbons.
Natural gas and petroleum are the most important sources of fuels and raw materials for
the chemical industry. Natural gas contains chiefly methane, CH 4 , but other alkanes, such
as:"ethane,CH 3 -CH 3 , and propane, CH 3 -CH 2 -CH 3 , are also present. Alkanes
react with chlorine at temperatures above 250°C to give chloroalkanes:
CH 4 + Cl 2 -+ CH 3 C1 + HCI
methane chloromethane
CH 3 -CH 3 + Cl 2 -+ CH 3 -CH 2 C1 + HCI
ethane
chloroethane
The IUPAC names of chioro alkanes, and ofhalogenoalkanes
are derived from the name of the corresponding alkane.
in general,
Alkane
Halogenoalkanes
CH 4 CH 3 C1 CH 2 C1 2
methane chloromethane dichloromethane
CHCl 3 CCl 4
trichloromethane tetrachloromethane
CH 3 -CH 3 CH 3 -CH 2 Br CH 3 -CH 2 F
ethane bromoethane fluoroethane
Ouestions
1 What are the IUPAC names ofCHBr 3 , CH 3 -CH 2 I, and CH 2 F 2 ?
2 What are the structural formulae of (a) tetrabromomethane,
(b) chloroethane?
The answers to B2 are given on page 15. More generally answers are
opposite or below the corresponding questions.
~ B3 after checking your answers. (You should write down all your
answers so that you can check them precisely.)

14 Programmed sections
It is important to note that structural formulae do not depict geometric
H H
features ofa molecule (see A7). H -C-CI and CI-C-CI both
CI
H
represent the same compound, dichloromethane. This is discussed in
some detail in the optional exercises in 3.1, Chapter 3.
»)~ B4 if you had any difficulties in answering the questions in B2;
otherwise B5.
I
I
I
I
83
Optional
See questions in B2.
84
1 CHBrj
This compound is derived from methane, CH 4 , by replacing three
hydrogen atoms by bromine; it is called tribromomethane.
CH 2 F 2
The name, difluoromethane, indicates that two hydrogen atoms of
methane have been replaced by fluorine.
CH 3 -CH 2 1
This is derived from ethane, so it is called iodoethane.
2 a. Tetrabromomethane This is derived from methane, that is, it contains
one carbon atom. The name shows thatfour hydrogen atoms in methane
Br
have been replaced by bromine. The formula is: Br-C- Br
I
Br
b. Chloroethane One hydrogen atom in ethane, CH 3 - CH 3 , has been
replaced by chlorine. The formula is: CH 3 -CH 2 Cl.
I

Programmed sections 1 5
Structural isomers - chloropropanes
Monochlorination of ethane yields chloroethane, CH 3 -CH 2 CI (see
B2). The optional question below deals with the chlorination of propane.
Attempt this question if you wish; otherwise go on to B6.
Optional question
How many different compounds can be obtained by replacing one
hydrogen atom in propane, CH 3 - CH 2 - CH 3 , by chlorine? (D se
models if available; the second table in B6 includes the answer to this
question.)
)))))00-+ B 6
85
Answer to 82
1 Tribromomethane, iodoethane, difluoromethane
Br
I
2 a. CBr 4 , Br-C-Br
I
Br
(Both are correct
answers.)
)))))00-+ B 3
H H H CI
I I I I
b. CH -CH CI H-C-C-CI H-C-C-H
3 2' I I ' I I
H H H H
(All correct answers, see 3.1, Chapter 3, particularly exercise 2.)
Note
Trivial names are sometimes used for some of the above compounds;
for instance, ethyl chloride for chloroethane, and bromoform for
tribromomethane. It is not important to remember these names at this
stage.

16 Programmed sections
Monochlorination of alkanes sometimes yields a single compound; in other cases two or
more different compounds are formed.
86
Alkane
Monochloroalkane
Boiling
Boiling
point;oC Formula Name point;oC Formula Name
-162 CH 4 methane -24 CH 3 Cl chloromethane
-89 CH 3 -CH 3 ethane 13 CH 3 -CH 2 CI chloroethane
-45 CH 3 -CH 2 -CH 3 propane 46 CH 3 -CH 2 -CH 2 CI (see below)
A
37 CH 3 -CH-CH 3 (see below)
I
Cl B
Monochloro derivatives of propane, A and B, have the same molecular
formula, C 3 H 7 CI, but different structural formulae. Compounds of this
type are called structural isomers. The name 'chloropropane' could
represent either A or B. The names of the structural isomers A and B
must be qualified so that only one structural formula can be deduced
from each name. This is an essential feature of the systematic name of a
compound (see BI).
Naming
isomeric chloropropanes
3 2 1 1 2 3
The chain of carbon atoms is numbered
CH 3 -CHz -CHzCl CH 3 -CH-CH 3
in such a way that the carbon atom to
I
which the substituent chlorine is
Cl
attached has the lowest possible
number. A B
The name of the compound indicates l-chloropropane 2-chloropropane
the position of the chlorine atom. (Note
the hyphen.)
Note
l-chloropropane
is pronounced one-chloropropane.

Programmed
sections
17
Ouestion
The formula of pentane is CH3 - CHz - CHz - CHz - CH3, or more
concisely CH3CHzCHzCHzCH3'
The compound CH3CHzCHzCHCH3
I
A 4chloropentane, CI
B 4-chloropentane,
c 2chloropentane,
D 2-chloropentane.
(Choose the correct term.)
is named:
~ B7 if you need help. Check your answer before proceeding further.
B9 if your answer is correct; otherwise B8.
Optional
Read B6 again. The numbering of carbon atoms in compounds A and B
is explained in more detail below.
Compound B Numbering the carbon chain in either direction makes
no difference to the name, 2-chloropropane.
1 Z 3
CH -CH-CH
3 I 3
CI
3 Z 1
CH -CH-CH
3 I 3
CI
Compound A In this case the carbon to which the chlorine is attached
must be given the lowest possible number.
3 Z 1
CH 3 -CHz-CHzCI
l-chloropropane
(correct)
Attempt the question in B6.
1 Z 3
CH 3 -CHz-CHzCI
3-chloropropane
(incorrect)
87
Answer to 86
2-chloropentane (note the hyphen).
~ B8 if you had any difficulties; otherwise B9.

18 Programmed sections
Optional
See question in B6.
88
The carbon chain must be numbered in the correct direction.
(Carbon to which chlorine is attached
has the lowest possible number.)
Correct name: 2-chloropentane
1 2 3 4 5
CH 3 CH 2 CH 2 CHCH 3
I
Cl
4-chloropentane is not correct
is not correct.
}l»~
B9
Isomeric dichloropropanes
You may wish to attempt the optional question given below, otherwise
go on to BIO.
Optional question
Monochlorination of propane yields two structural isomers,
l-chloropropane and 2-chloropropane (see B6). What are the structural
formulae of isomeric dichloropropanes? (Dse models if available; BI0
includes the answer to this question.)
}))}~ BIO
89

Pregrarnrned sections
19
810
Four different structural isomers (compounds C, D, E, and F) have the
same molecular formula, C 3 H 6 Clz. The structural formulae and
systematic names of two of these are:
c
CI
I
CH -C-CH
3 I 3
Name .J ,2-dichloropropane 2,2-dichloropropane
Note
1. Numbering of the carbon chain.
2. Pu"nctuation (comma, hyphen).
3. Each substituent is assigned a number. Compound D is not named
2-dichloropropane.
Ouestion
The structural formulae of the remaining two isomeric dichloropropanes
are:
D
CI
CICHz-CHz-CHzCI
E
F
What are the systematic names ofE and F?
~ BII if you need help. Check your answer before proceeding further.
Bl4 if your· answer is correct; otherwise B12.
Answer to B 1 0
E CH 3 - CHz - CHClz: 1,l-dichloropropane
F CICHz-CHz-CHzCI: 1,3-dichloropropane
Check your answer carefully.
~ Bl2 if you had any difficulties; otherwise B14.

20 Programmed sections
811
Optional 3 2 1
E Number the carbon chain correctly CH 3 -CH 2 -CHC1 2 • Compare
this formula with the formula of 2,2-dichloropropane, D in BIO.
F Number the carbon chain, and compare F with the formula of
1,2-dichloropropane in BIO.
Attempt the question in BIO.
812
Optional
CH 3 -CH 2 -CHCI 2 , or more simply CH 3 CH 2 CHCI 2 , is a
'dichloropropane', that is, a compound in which two of the hydrogen
atoms of propane have been replaced by chlorine (see expanded
formula).
H H H
I I I
H-C-C-C-CI
I I I
H H CI
The name of the compound must indicate to which carbon atom the
chlorine atoms are bonded. Hence we number the carbon atoms in the
chain.
Question
Which of the following is numbered correctly? (Give a reason.)
}}~ B13. (This includes the answer to the above question.)

Programmed
sections
21
......................................................................................................................... / .
813
Optional
The carbon chain in CH 3 CH 2 CHCI 2 is numbered so that the lowest
possible number is given to the carbon atom to which substituent
chlorine atoms are bonded. The compound is then named as shown
below.
321
CH 3 -CH 2 -CHCI 2
: ; : :
I I, I1tichlof(~propane I
1 c 1 b : a j
~ ~ J }
a propane Three carbon atoms bonded as in propane, CH 3 CH 2 CH 3 •
b dichloro Two chlorine atoms have replaced two hydrogen
atoms of propane.
c 1,1- Both chlorine atoms are linked to carbon atom I. (Each substituent
is given a number; I-dichloropropane is incorrect.)
Similarly
321
CICH 2 - CH 2 - CH 2 CI
r···········:·····················:··················· ..... :
I l,3lIichloropropane
; c; b i a j
~ t J ~
i
~ B14 (Solid lines as below indicate suitable points at which to interrupt
your work.)

22 Programmed sections
Structural formulae deduced from systematic names
Isomeric dichloroethanes
1,2-dichloroethane is produced commercially in larger quantities than any other organic
chlorine compound. It is used in the manufacture of PVC (polyvinyl chloride), a synthetic
polymer.
Ouestion
What is the structural formula of 1,2-dichloroethane?
»)))~ Bl6 if your answer is correct; otherwise BI5.
B14
Optional
Structural formula of 1,2-dichloroethane. The systematic name of a
compound can be 'translated' into a structural formula (see BI). This is
best done in stages, writing down the carbon chain first (see a below),
then the sub~tituents (see b and c). The formula is completed by adding
hydrogen atoms.
: : : ;
! I ,2-~ichloro~thane !
i c i b i a i
i } ~ , ~
1 2
a ethane Two carbon atoms as in ethane, i.e. C-C
B15
b dichloro Two chlorine atoms have replaced two hydrogen atoms
c 1,2- The chlorine atoms are linked to carbon atoms I and 2,
i.e.
»>~ BI6
1 2
CI-C-C-Cl.
The formula can now be completed by inserting the correct number of
hydrogen atoms (each carbon must be bonded to other atoms by four
single bonds) :
H H
I I
CI- C- C- CI,that is, CICH 2 CH 2 CI
I I
H H

Programmed sections
23
816
1,2-dichloroethane (see B14) is produced in very large quantities by reacting ethene
(alternative name ethylene) with chlorine. The reaction between ethyne (acetylene) and
hydrogen chloride yields a structural isomer of 1,2-dichloroethane.
CHz=CHz
ethene
CH=CH
ethyne
+ Clz -+ ClCHz-CHzCI
+ 2HCI -+ CH 3 -CHClz
Ouestion
What is the systematic name of CH 3 - CHCl 2 ? (Check your answer
carefully.)
~ B 18 if your answer is correct; otherwise B 17. (Solid lines such as the one
above Bl8 indicate suitable points at which to interrupt your work.)
Answer to B 1 4
CICH 2 -CH 2 CI,
H
CI
I I
CI-C-C-H
I I
H H
(All correct
answers.)
H
I
H
I
I
H
I
H
'
CI-C-C-CI
~ B15 if you had any difficulties; otherwise B16.
Answer to B 1 6
CH 3 - CHCI 2 : 1,I-dichloroethane.
~ B 17 if your answer was not correct; otherwise B 18.

24 Programmed sections
Optional
2 1
CH 3 -CHCI 2
; : ; :
! 1,11Iichloro~thane !
i c i b i a i
1 E ; ~
(Note the numbering of the carbon chain.)
817
a Two carbon atoms, C-C: ethane.
b Two chlorine atoms as substituents, C-CCI 2 : dichloroethane.
c Both chlorine atoms bonded to carbon I : 1,l-dichloroethane.
(The position of each atom indicated separately,
note hyphen.)
The optional question below may help you further. Work through this
if you wish; otherwise B18.
Optional question
Give reasons why each of the following is not the correct systematic
name ofCH 3 -CHCI 2 •
a. l-dichloroethane,
b. 1,l-chloroethane,
c. 2,2-dichloroethane,
d. I-1-dichloroethane.
)))~ BI8
Formula of 1,1 ,2-trifluorobutane
Ouestion
What is the structural formula of 1,I,2-trifluorobutane?
butane: CH 3 CH 2 CH 2 CH 3 .)
818
(For reference,
)m~ B20 if your answer is correct; otherwise B19.

Programmed sections
25
Answer to B 1 7
a. l-dichloroethane:
each substituent must be allocated a number, 1,I-dichloroethane.
b. 1,l-chloroethane :
the presence of two chlorine atoms must be shown by the prefix di-,
l,l-dichloroethane.
c. 2,2-dichloroethane:
lowest possible number allocated to carbon atom bonded to substituents,
2 1
CH 3 CHCI 2 •
d. I-l-dichloroethane:
punctuation must be correct, I, I-dichloroethane.
»»>-+ BI8
Jl~nswerto B 1 8
1,1,2-trifluorobutane:
CH 3 CH 2 CHFCHF 2 •
Note
You may have written the formula in other ways, for instance
F F
I I
P-CH -CH-CH 2 -CH 3 • The important point to note is that two
fluorine atoms are attached to a carbon atom at the end of the chain and
one fluorine atom to the next carbon atom.
»»>-+ BI9 if you had any difficulties; otherwise B20.

26 Programmed sections
Optional
a
: : : :
I 1,1,2-~rifluoro~utane I
! c! b ! a j
~ ~ '" ~ ~
432 1
Four carbon atoms (butane), C-C-C-C.
b Three fluorine atoms have replaced three hydrogen atoms.
432 1
c Fluorine atoms are linked as shown C-C-C-C- F.
I I
F F
819
Completing the formula
H H H H
I I I I
H-C-C-C-C-F, or CH CH CHFCHF .
I I I I 3 2 2
H H F F
»))))-00+ B20
820
IUPAC names of alkanes
Alkanes are hydrocarbons in which each carbon atom is linked to other
atoms by four single bonds. (A hydrocarbon contains only carbon and
hydrogen.) The ending -ane is used for the systematic names of alkanes
and their simpler derivatives.

Programmed
sections
27
The IUPAC names of the first four alkanes do not follow any logical
pattern and must be memorized. Higher alkanes mostly have names,
which are based on Greek numerals; hexane, for example, contains a
chain of six carbon atoms.
Number of
carbon atoms
in chain Name Formula
1 methane CH 4
2 ethane CH 3 CH 3
3 propane CH 3 CHzCH 3
4 butane CH 3 (CH z hCH 3
5 pentane CH 3 (CH z hCH 3
6 hexane CH 3 (CHz )4CH3
7 heptane CH 3 (CHz)sCH 3
8 octane CHiCHz)6CH3
The names of the first eight alkanes are given above; a more extensive
list can be found in 4.6a. Note that CH3CH2CH3 corresponds to
CH3-CH2-CH3. Note also how structural formulae of alkanes can
be contracted further: hexane, CH3CH2CH2CH2CH2CH3, is
contracted to CH3(CH2)4CH3'
Ouestion
The names given below contain one or more mistakes. Give correct
IUPAC names. (If necessary consult the above table.) Write your
answers down and check them carefully (see page 29).
a. CH3(CH2)sCHBr2: 1-dibromoheptane.
b. CH3CH2CHC1CH2CH2C1: 3,5-dich10robutane.
c. CH3CH2CHBrCH2Br: 1-2-dibromobutane.
d. CH3CH2CC13: 3-trichloropropane.
e. CH3(CH2)2CF 2CH:iCHF 2: 1,3-tetrafluorohexane.
))B)o-o+ B 21

28 Programmed sections
821
Halogenoalkanes containing more than one halogen
Many of these 'mixed' halogenoalkanes are of commercial importance,
for instance those mentioned in the question below. Points to note
include:
H
I
1 Alphabetic order of substituents: bromochloromethane, H - C - Cl.
I
Br
2 Where numbering is necessary, each halogen is numbered 'separately':
1 z
l-bromo-2-chloroethane, BrCHz - CH 2 Cl.
3 Bromo, dibromo, tribromo, etc., are all considered to start with b:
I
I
tribromoiodomethane,
Br- C- Br.
I
Br
The above rules are important for indexing carbon compounds, and
hence for looking up particular compounds in reference books.
Ouestion
Choose the correct IUPAC name from the alternatives given below:
Compound
Name
I
I
F-C-F A iodotrifluoromethane B trifluoroiodomethane
I
F
H Cl
I I
H-C-C-F c l-chloro-l, I-difluoroethane D 1,1,l-chlorodifluoroethane
I I
H F
~~ B22

Programmed sections
29
Answer to 820 1
a. 1,1-dibromoheptane, CH 3 (CH2)sCHBr2
The position of each bromine atom must be indicated by a number;
I-dibromoheptane is wrong.
5 4 3 2 1
b. 1,3-dichloropentane, CH 3 CH2CHCICH2CH2CI
Five carbon atoms (pentane); butane is wrong.
Lowest possible number for substituents; 3,5-dichloro is wrong.
2 1
c. 1,2-dibromobutane, CH2CH2CHBrCH2Br
Punctuation must be correct (comma between numbers);
1-2-dibromobutane is wrong.
.~ B21
3 2 1
d. 1,1,1-trichloropropane, CH 3 CH2CCl 3
Lowest possible number for substituents, number allocated to each
substituent; 3-trichloropropane is wrong.
e. 1,1,3,3-tetrafluorohexane, CH 3 (CH2hCF 2CH2CHF 2
Four fluorine substituents; the position of each must be shown;
1.3-tetrafluorohexane is wrong .
Answer to 821
I
I
F- C- F trifluoroiodomethane, B is correct.
I
F
)))))-00+- B 22
H
I
Cl
I
H - C- C- F l-chloro-l, I-difluoroethane, c is correct.
I
H
I
F
Read B21 again if you had any difficulties.

30 Programmed sections
822
Condensed structural formulae
Contracted (condensed) structural formulae can be written in a number
of different ways, for instance:
Expanded formula
Condensed formula
H H ClzCH-CHClz ClzCHCHClz
I I CHClz-CHClz CHClzCHClz
CI-C-C-CI
I I (Note. CC1 2 HCC1 2 H is not correct.)
Cl Cl
You will probably not find it difficult to interpret these condensed
structural formulae. Work through the optional question below if you
wish; otherwise go on to B23.
Optional question
Write expanded structural formulae for the following:
CH2BrCH2CH 2 CI, CF 3CH2CHFCH3.
(Answer on page 32.)
»~ B23
823
Summary
1 An organic compound is generally represented either by a structural
formula, or by a name. The systematic IUPAC name of a compound is
an internationally accepted equivalent of its structural formula. The
structural formula of a compound can be deduced from its systematic
name. Chemists however use non-systematic names of compounds for
some purposes (see Bl).
2 Structural isomers have the same molecular formula but different
structural formulae (see B6).

Programmed sections
31
3 A list of the IUP AC names of some alkanes is given in B20. The names
of halogenoalkanes are derived from the names of the corresponding
alkanes.
CH 3 1
iodomethane
CHBr 3
tribromomethane
The name of the halogen substituent comes before the name
of the alkane (see B2).
The presence of more than one substituent atom is
indicated by prefixes di-, tri-, and so on. (See B2 to B4.)
3 2 1
CH 3 CHCICH 3
2-chloropropane
3 2 1
CH 3 CH 2 CH 2 CI
l-chloropropane
Numbering of carbon atoms indicates the position of
substituents whenever this is necessary to distinguish
between structural isomers.
The carbon chain is numbered in the direction which gives
the lowest possible numbers to substituents.
Punctuation is important (hyphen in this case). (See B5
to B8.)
3 2 1
CH 3 CHCICH 2 Cl
1,2-dichloropropane
3 2 1
CH 3 CH 2 CHFCHF 2
1,1,2-trifluorobutane
Each substituent is assigned a number. Carbon chain
numbering is as before (to give lowest possible numbers to
substituents ).
Punctuation includes commas as well as hyphens. (See
B9 to B13, also BI9.)
CIF 3
trifluoroiodoethane
Different substituents are arranged in alphabetical order.
Trijluoro is considered to start with/for this purpose. So
trifluoro comes before iodo.
2 1 Each h'alogen substituent is numbered 'separately'
CH 3 CCIF 2
(See B21.)
l-chloro-l,l-difluoroethane
4 Condensed structural formulae can be written in a number of different
ways (see B22).
5 Further examples are given for assigning the correct systematic name to
a structural formula, and vice versa (see for instance B14, B16, B18,
and B20).
~ Review problems, Chapter 2,2.1.

32 Programmed sections
Answer to 822
Br H CI H H H
I I I I I I
CH 2 BrCH 2 CH 2 CI H-C-C-C-H (Br-C-C-C-Cletc.)
I I I I I I
HHH
HHH
CF 3 CH 2 CHFCH 3
F H F H
I I I I
F-C-C-C-C-H
I I I I
F H H H
Note
It is useful to write the carbon chain down first, giving-C-C-Cfor
the first compound, then add substituents such as Br and F.
)lD~
B23

Programmed
sections
33
Section C
Functional groups and systematic names
Most reactions of halogenoalkanes involve the halogen atom. The
action of aqueous sodium hydroxide, for instance, converts a
halogenoalkane into an alcohol, a compound containing an -OH,
hydroxyl group. Methanol and propan-l-ol are examples of alcohols.
CH 3 I + OH- -+ CH 3 0H + 1-
iodomethane
methanol
C1
CH 3 CH 2 CH 2 Br + OH- -+
1-bromopropane
CH 3 CH 2 CH 2 0H
+ Brpropan-l-ol
The halogen atom, which confers a characteristic type of reactivity upon
halogenoalkanes, is called the functional group of these compounds. In
general organic compounds are -classifiedinto different series, each of
which contains a characteristic functional group. Without this kind of
systematic classification, the study of the vast number of known
carbon compounds (see AI) would be extremely complex. Three
examples of functional groups are given below (see optional sections
4.7a, 4.7b, and 4.7c in Chapter 4 for a more extensive list).
Series of compounds
in which this group
Functional group occurs Example
- Cl, or other halogen halo genoalkanes CH 3 CHzBr, bromoethane
-OH, hydroxyl alcohols CH 3 CHzOH, ethanol
-NOz, nitro nitroalkanes CH 3 CHzNOz, nitro ethane
Note
Propan-l-ol
is pronounced propan-one-ol.

34 Programmed sections
The systematic name of a compound indicates which functional group
is present. The ending -01, for instance, shows the presence of a hydroxyl
group.
Ouestion
The formula ofpentan-3-01 is A CH3CHzOCHzCHzCH3
B CH3CHzCHCHzCH3
I
OH
Choose the correct term giving a reason. (The answer is given opposite.)
)})J~
C2
IUPAC names of alcohols (functional group: -OH)
The substituent functional group in halogenoalkanes is indicated by
means of a prefix placed before the name of the alkane. The hydroxyl
functional group in alcohols is shown in their IUPAC names by the
suffix -01, as in methanol, CH 3 0H. The ending 'e' of the alkane is
omitted (to avoid two vowels following one another) so ethane plus 01
is ethanol, CH3CHzOH. For longer chain alcohols:
C2
4- 3 2 1
Carbon atoms are numbered so that the carbon CH 3 CH 2 CHCH 3
atom to which the hydroxyl group is attached
I
has the lowest possible number (compare B6).
OH
butan-2-ol
The 'e' ending of the alkane is dropped (as in
methanol and ethanol).
butan-2-01 not
butane-2-01
Note the use of hyphens either side of the
relevant number (butan 2-01is not correct).
Note
Butan-2-01 and pentan-3-01 are pronounced butan-two-ol
pentan-three-ol.
and

Programmed sections
35
Ouestion
Write structural formulae for propan-2-01 and butan-I-ol (two
technically important alcohols).
Note
Write down your answers to questions in this section so that you can
check them precisely.
>m~ C3 if your answers are correct; otherwise C4.
Answer to C1
Pentan-3-01, B: CH 3 CH 2 CHCH 2 CH 3 • The name of this compound
I
OH
ends in -oi, so the hydroxyl functional group is present.
~ C2
Answer to C2
Propan-2-01: CH 3 CHCH 3 , or CH 3 CH(OH)CH 3 .
I
OH
Butan-I-ol: CH 3 CHzCHzCHzOH.
~ C3 if your answers are correct; otherwise C4.

36 Programmed sections
Alcohols containing two or more hydroxyl groups
These are named as follows.
C3
Two substituent hydroxyl groups are indicated as shown
on the right. The 'e' ending of the alkane is retained in
this case, since we do not have two consecutive vowels.
Note the punctuation carefully.
4 3 2 1
CH 3 CH 2 CHCH 2 0H
I
OH
butane-I,2-diol
Three hydroxyl groups are shown similarly. (Note.
trivial name ofpropane-I,2,3-triol is glycerol.)
The
1 2 3
HOCH 2 CHCH 2 0H
I
OH
propane-I,2,3-triol
Many of these compounds are commercially useful. For example:
Trivial name
Examples of uses
HOCH 2 CH 2 OH glycol manufacture ofTerylene; non-volatile
antifreeze for car radiators; substitute for
A
glycerol in technical applications.
CH 3 CHCH 2 OH propylene non-toxic substitute for glycerol in food and
I glycol cosmetic applications; manufacture of
OH
synthetic resins.
B
Ouestion
What are the IUPAC names of glycol (A in the above table) and
propylene glycol (B)?
)))})o-+- C7 if your answers are correct; otherwise C5.

Programmed sections 37
Optional
C4
! : : :
j butanL 1-61 ~
I a! c!b !
: : : :
a butan Four carbon atoms linked as in butane
4 3 Z 1
C-C-C-C
b 01 Hydroxyl group present.
c -1- Hydroxyl group linked to terminal carbon atom (at end of chain).
4 3 Z 1
C-C-C-C-OH
Formula completed:
H H H H
I I I I 4 3 Z 1
H-C-C-C-C-OH,
i.e. CH 3 CH z CHzCHzOH
I I I I
H H H H
A similar method can be used to deduce the formula ofpropan-2-01.
; ~ ~ ~
1 propan~2-pl !
i a i c ib :
; ; ~'" ;
~ C3 (subsection before this one).
3 Z 1
CH -CH-CH
3 I 3
OH
Answer to C3
A ethane-l,2-diol B propane-l,2-dio1.
Check carefully the following points: numbering, the ending 'e' retained
in the name of the corresponding alkane, punctuation.
»»>-+ C7 if your answers were correct; otherwise C5.

38 Programmed sections
Optional
----------------------------------------,
three carbon atoms, C-C-C, hence: propane
two hydroxyl groups, hence: diol
C5
Carbon chain is numbered to show position of hydroxyl groups
(lowest possible numbers).
IUP AC name: propane-l ,2-diol (ending e retained).
Note
1 2 3
1. Propane-2,3-diol, corresponding to CH 3 CHCH 2 0H, is not correct.
I
OH
2. The IUPAC name of HOCH 2 CH 2 0H can be worked out in a similar
way.
Optional
Give the IUP AC names of
a. CH 3 CH 2 CH 2 CHCH 3 and
I
OH
b. CH 3 CH 2 CHCHCH 3 •
I I
HO OH
C6
»))))-+ C7 if your answers are correct; otherwise work through from C2 again.

Programmed sections
39
Alkenes
Alkenes, a series of compounds obtained mainly from petroleum, are
probably the most important basic raw materials used in the organic
chemical industry. Ethene, CHz=CHz, and propene, CH 3CH=CHz,
are typical alkenes. The trivial names ethylene and propylene are widely
used for these compounds.
The manufacture of alkenes is expanding rapidly. British ethylene production is expected
to expand by 200 per cent between 1965and 1970. The corresponding United States
increase is forecast to be 250 per cent between 1970and 1980. The expansion in production
of industrial chemicals, particularly organic chemicals yielding synthetic plastics, fibres,
rubber, and pharmaceuticals, can be taken as a measure of the increasing prosperity ofa
country. (This and other factors relating to future economic growth in the United States
is discussed in an article called 'Outlook 70s' by W. S. Fedor in Chemical and Engineering
News (I 969),47,52, p. 96.)
C7
Figure 6
Two models of ethene, C ZH4
.
Figure 6 shows models of ethene (ethylene). Compare these with the
models ofethane in figure 2, AI. You may also find it useful to read
part ofsection 4.5a, which contrasts the reactions of alkanes and alkenes.
Answer to C6
a. pentan-z-ol. (Note. Numbering; 'e' ending deleted.)
b. pentane-2,3-diol. (Note. Numbering; 'e' ending retained.)
~ C7 if your answers are correct; otherwise work through from C2 again.

40 Programmed sections
"" /
The functional
.
group in alkenes is the
/
C= C
"'-
group. Most reactions
of alkenes involve this group. Bromine, for instance, adds to the double
bond to form a dibromoalkane:
CHz=CHz + Brz ~ Br-CHz-CHz-Br
1,2-dibromoethane
"'- /
The presence of the C== C group is indicated by the suffix, -ene.
/ "'-
H H
"'- /
C=C
/ "'-
H H
j ~·~~~~~ .. ·.. ·l
1. ~ .. .1. .. ~ 1
a eth Two carbon atoms (compare ethane, CH 3 CH 3 ).
"" /
bene C= C group present.
/ ""
Questions
1 Which functional groups are present in each of the following:
a. pentan-2·01,
b. propene,
c. butane-l,3-diol,
d. chloroethene?
(Note. Some compounds contain two or more different functional
groups.)
2 How many carbon atoms are there in each of the above compounds?
)J~
C8

Programmed sections
41
IUPAC names of alkenes
C8
Formula of alkene
IUPACname
of alkene
4 3 2 1
CH 3 CH 2 CH=CH 2
1 2 3 4
CH 3 CH=CHCH 3
~ ':'······-··'1
eth~ne
aib
prop~ne
a :b
t ~ j
........
but~l-ene
a!c:b
~ ~ J j
: ; ; :
bui.-2-~ne
a:c!b
....................................
a Number of carbon atoms, two in ethene,
four in but-l-ene.
"- /
b C=C present (suffix -ene), for
/ -",-
instance propene.
"- /
c Position of C=C group, for
/ "-
4 3 2 1
instance CH 3 CH 2 CH=CH 2 , but-I-ene.
i. A single number shows a double bond
between two carbon atoms, atoms I and 2
in this case. Correct name: but-l-ene.
(But-I ,2-ene is wrong.)
ii. The single number used is the lower of
the two involved in the bond. (But-2-ene is
wrong for CH 3 CHzCH=CHz.)
iii. The chain is numbered to give the
lowest possible number,
4 3 2 1
CH 3 CH 2 CH=CH 2 • (But-3-ene is
wrong.)
Note. Study this table in detail. The trivial names ethylene and propylene
are widely used (instead of ethene and propene).
Answer to C7
1 a. -OR (hydroxyl group).
d. -CI and" C=C /.
/ '"
2 a. five. b. three. c. four.
'" /
b. C=C
/ -'"
d. two.
c. -OR (two groups).
(Note. Study the tables of names of alkanes in B20, if your answers to
this question are not correct.)

42 Programmed sections
Isomeric alkenes
Alkenes are obtained in vast quantities from petroleum sources. In the laboratory they are
generally prepared from alcohols or halogenoalkanes. A mixture of products is obtained
in many cases.
CH 3 CH z CH z CHBrCH 3 KOHin) CH 3 CH z CH=CHCH 3 , CH 3 CH z CH z CH=CH z
ethanol
A B (71 %) C (29%)
Uuestions
1 What are the IUPAC names of A (CH3CH2CH2CHBrCH3),
B (CH3CH2CH=CHCH3), and C (CH3CH2CH2CH=CH2)? (Study
the table on page 41 again if you have difficulty with B and C.)
2 Is compound B (CH3CH2CH=CHCH3) an isomer of
C (CH 3 CH2CH2CH=CH 2 )? Give a reason. (If you need help, see B6
and BIO for examples of isomeric compounds. Structural isomers are
discussed in greater detail in 4.2.)
)>>l~ CII if your answers are correct; C9 if your answers to question 1are
not correct; CIO if your answer to question 2 is not correct.
Optional
Study the table in C8 again, then answer the question below.
Ouestion
The following names contain one or more mistakes. Give correct
IUPAC names.
a. CH3CH2CH2CH2CHBrCH3: 5-bromopentene.
b. CH3CH=CHCH2CH2CH3: hex-2,3-ene.
c. CH3CH=CHCH 2 CH3: pent-3-ene.
(Check your answers carefully.)
»)~ CII if your answer to question 2 in C8 was correct; otherwise CIO.
C9

Programmed sections
43
Answer to C8
s 4 3 2 1
1 A CH3CH2CH2CHBrCH3: 2-bromopentane;
S 4 3 2 1
B CH3CH2CH=CHCH3: pent-2-ene;
S 432 1
C CH3CH2CH2CH=CH2: pent-I-ene.
(Check your answer carefully.)
2 B is an isomer of C, because both compounds have the same molecular
formula, CSH lO •
~ CII if your answers are correct; C9 if your answers to question 1 are not
correct; CIO if your answer to 2 is not correct.
Answer to C9
6 5 4 3 2 1
a. CH3CH2CH2CH2CHBrCH3: 2-bromohexane. (Six carbon atoms,
'" /
hence hex, not pent; C= C absent, ane, not ene; lowest possible
/ "-
number for substituent, 2- not 5.)
1 2 3 4 S 6
b. CH3CH=CHCH2CH2CH3: hex-2-ene. (A single number shows a
double bond between two carbon atoms, see C8; hex-2-ene not
hex-2,3-ene.)
1 2 345
C. CH3CH=CHCH2CH3: pent-2-ene. (The single number showing
the presence of a double bond is the lower of two, see C8; pent-2-ene
not pent-3-ene. Note also the numbering of the carbon chain:
5 4 321
CH3CH=CHCH2CH3 is not correct.)
~ CII if your answer to question 2 in C8 was correct; otherwise CIO.

44
Programmed sections
48
Programmed sections
C15
Optional
;~eh[~~~f';~:i
1 2 345 6 7
a Itepta Sevencarbon atoms C-C-C-C-C-C-C.
'" /
b diene Two C==C groups present.
/ "
c -2,4- Double bonds between carbon atoms 2 and 3, 4 and 5
1 2 345 6 7
C-C==C-C==C-C-C.
»>>>-+ Cl4
Completing the formula:
H H H
I I I
H - C- C==C- C= C- C- C- H or
I I I I I I I
H H H H H H H
1 2 3 4 567
CH 3 CH = CHCH ==CHCH 2 CH 3 •
C16
Cyclic carbon compounds
We have dealt so far only with compounds which contain a simple chain
of carbon atoms. Many cyclic carbon compounds are known.
Some of these occur in natural products, others are manufactured. Cyclopropane, for'
instance, has been used as an anaesthetic. Cyclohexane is one of the most important
petroleum-based chemicals. A large proportion of the cyclohexane production is used for
the manufacture of nylon.

Programmed sections
45
Question
Give the IUPAC names ofD (HOCH 2 CH 2 CHzCH 2 0H) and
E (CH 2 = CH - CH = CH 2 ). (See C3 if you need help with the name
of D.)
))))}-+ C13 if your answers are correct; otherwise C12.
Answer to C1 0
A and C are isomeric. Both have molecular formula C 4 H 10 0. The
molecular formula ofB is C 4 HsO. (Note. Some isomers such as A and C
do not have the same functional group; others such as Band C in C8 do
have the same functional group.)
))))}-+ Cll
Answer to C11
1 234
D HOCHzCH 2 CHzCHzOH:
1 234
butane-I,4-diol.
C CH 2 =CH-CH=CHz: buta-I,3-diene.
(Check your answer carefully.)
))))}-+ Cl3 if your answers are correct; otherwise C12.

46 Programmed sections
C12
Optional
Study the tables in C3, C8, and CII, then answer the question below.
Question
The following names contain one or more mistakes. Give correct names.
a. HOCH 2 CH 2 CH 2 0H: butan-I-3-diol.
b. CH 3 -CH=CH-CH 2 -CH=CH 2 : hex-2,S-diene.
c. CH 2 ==CH-CH 2 -CH==CH 2 : penta-l,2,4,5-diene.
~ C13
C13
Ouestion
What is the structural formula ofhepta-2,4-diene? (The formula of
heptane is CH 3 (CH 2 )sCH 3 .)
:~ Cl4 if your answer is correct; otherwise CIS.

Programmed sections
47
~ Cl6
C14
The presence ofa -C=C- group is indicated by the suffix -yne. This
is the functional group present in alkynes, such as CH=CH, ethyne
(commonly acetylene). The rules for naming these compounds, which
are very similar to those for alkenes, are dealt with in the next section,
Section D (DI).
Answer
~ Cl3
to C12
123
a. HOCH 2 CH 2 CH 2 0H: propane-I,3-dio1. (Three carbon atoms, hence
propane; comma between numbers I and 3; propane.)
6 5 432 1
b. CH 3 CH=CHCH 2 CH=CH 2 : hexa-I,4-diene. (Carbon chain
numbered to give lowest numbers; hexa-, not hex-, before diene.)
12345
c. CH 2 =CH -CH 2 -CH=CH 2 : penta-I,4-diene. (Two numbers
sufficient to show presence of two double bonds.)
Answer to C 1 3
CH 3 CH=CHCH=CHCH 2 CH 3 • (Check your answer carefully; you
may have written an expanded formula.)
~ Cl4 if your answer is correct; otherwise C15.

48 Programmed sections
Optional
:··················.···········:················1
I hepta,L2,4~iene I
~ a~c~b!
; ~ ~ ~
1 2 345 6 7
a hepta Seven carhon atoms C-C-C-C-C-C-C.
b diene
'" /
Two C=C
."
groups present.
/
c -2,4- Double bonds between carbon atoms 2 and 3,4 and 5
1 2 345 6 7
C-C=C-C=C-C-C.
C15
Completing the formula:
H H H
I I I
H-C-C=C-C=C-C-C-H
I I I I I I I
H H H H H H H
or
1 2 3 4 567
CH 3 CH=CHCH=CHCH 2 CH 3·
C16
Cyclic carbon compounds
We have dealt so far only with compounds which contain a simple chain
of carbon atoms. Many cyclic carbon compounds are known.
Some of these occur in natural products, others are manufactured. Cyclopropane, for'
instance, has been used as an anaesthetic. Cyclohexane is one of the most important
petroleum-based chemicals. A large proportion of the cyclohexane production is used for
the manufacture of nylon.

Programmed sections
49
IUPAC names and structural formulae of cycloalkanes
and related campau nds
Names are similar to those of open chain compounds, for instance:
CH=CH
/ '"
CHz
~/
CH z
CHz
a
b
: : :
: cyc10bentbne I
1 ~ I ~ .1..~ 1
Five carbon atoms.
These atoms arranged in a 'ring'.
'" /
cane C= C bond present.
/ '"
Other examples of cyc10alkanes
CHz-CHz
"(/
CHz
cyclopropane
CHz-CHz
I
CHz-CHCI
chlorocyclo butane
I
Question
Write structural formulae for cyc1ohexane, cyc1ohexene, and
cyc1ohexanol.
~ CI8 if your answers are correct; otherwise CI7.
Answer to C16
CHz
/ "(
CHz
I
CHz
CH z CH z
"( /
CHz
cyclohexane
I
CHz
/ "(
CHz
I
CHz
"( /
CH
II
CH
CHz
cyclohexene
CHz
/ "(
CHz
I
CHz
CH z CHOH
"( /
CHz
cyclohexanol
~ CI8 if your answers are correct; otherwise CI7.
I

50 Programmed sections
Optional
Taking cyc1ohexanol as an example:
: : : :
I cyc1~hexan,~1i
i b i a ic j
~ ~ J. ~
a hexan Six carbon atoms linked by single bonds, as in alkanes.
C
I
C
C
/ '"
." /
C
C
I
C
b cyclo These carbon atoms are arranged in a ring.
C17
e 01 Presence of one hydroxyl group as substituent; all the carbon atoms
are equivalent in the ring, hence the hydroxyl group can be attached to
anyone of these.
."
C
/
C C
I
C
." /
C
I
C-OH
The formula is completed as shown below.
CH 2
/ '\
CH 2 CH 2
I I
CH 2 CHOH
'\ /
CH 2
»}})-+ Cl8

Programmed sections
51
C18
You will find it instructive to build models ofsome ofthe cyclic
compounds given in C16. Others are mentioned in the next section,
Section D, and review problems 10 (2.2), 25 and 26 (2.5). Figure 7 shows
models of cyclohexane in a particular rotational position. Note once
again that a structural formula does not give a direct indication of
molecular shape (see A7 and 3.1). The carbon atoms in cyclohexane and
cyclohexanol are not arranged as a simple hexagon in one plane. These
molecules are flexible and can adopt different rotational positions. You
may find it useful to compare figure 7 with the illustrations of the
benzene molecule in figure 8, D2.
Figure 7
Cyclohexane, C6H12: skeletal and ball-and spoke models.
»»>--+ C19

52 Programmed sections
C19
Isomers of butane and pentane
Compounds, such as pentane, CH3-CHz-CHz-CH2-CH3' have
an unbranched (continuous) chain of carbon atoms. It is important to
note that the carbon atoms in this type of chain are not arranged in a
straight line. (See figure 2 in A2, and also A5.) Many organic compounds
contain branched chains of carbon atoms. The simplest compound with
a branched chain is 2-methylpropane, an isomer of butane.
Isomers ofmolecular formula C 4 H lO
butane
1 2 3
CH -CH-CH
3 I 3
CH3
P
2-methylpropane
P is considered to be: propane in
which one hydrogen atom has been
replaced by a - CH3 group (methyl
group) at carbon atom 2.
Note
The name methylpropane is an alternative name for P (see 4.4 in Chapter 4).
There are three isomers of molecular formula C S H 12 • Figures 3 and 4
in A2 and A4 illustrate models of these three isomers.
Compounds A and C (see table below) have in the past been given the trivial names of
isopentane and neopentane. (The trivial name for 2-methylpropane is isobutane.)
Longest continuous
chain of carbon
Formula IUPAC name atoms
CH3-CH2-CH2-CH2-CH2 pentane five atoms
B
1 2 3 4
CH -CH-CH -CH 2-methylbutane four atoms
3 I 2 3
CH3
A
CH3
I
CH -C-CH
3 I 3
2,2-dimethylpropane three atoms
CH3
C

Programmed sections
53
Ouestion
What is the IUP AC name of CH 3 -
CH 3
I
C - CH 2 -
I
CH 3
CH 3 ?
)))))0-+ C20
C20
Branched chain alkanes
The name of a branched chain alkane is based on the longest continuous
chain of carbon atoms. Other groups such as methyl groups are treated
as substituents. The chain is numbered in the direction which gives the
lowest numbers (A in C19 is 2-methylbutane, not 4-methylbutane). It is
best to write the longest continuous carbon chain horizontally, but this
is not always done for a variety of reasons. You should note again that
molecular shape is not shown in structural formulae.
Ouestion
The IUPACname ofCH 3 -CH-CH 2 -CH-CH 2 -CH 3 is
3,5-dimethylheptane/2,4-diethy
I
CH 2 CH 3 CH 3
lpen tane/nei ther.
Choose the correct term. (-CH 2 CH 3 is the ethyl group; the formula of
heptane is CH 3 (CH 2 hCH 3 .) (The answer is on page 55.)
I
)))))-+ C21
Answer to C19
CH 3
~ C20
1 134
CH 3 -C-CH 2 -CH 3 :
2,2-dimethylbutane.
I
CH 3
(Check details such as numbering and punctuation.)

54 Programmed sections
IUPAC names of branched
chain alkanes
1 z 3 4 5 6 7
CH 3 -CHz -?H -?H -CHz -CHz -CH 3
C21
CH 3 CH 3
1••••3,;f=:.::~t~:i.~~~ ••••• i
a heptane Seven carbon atoms in longest continuous chain.
b dimethyl Two methyl groups have replaced two hydrogen atoms.
c 3,4- Methyl groups linked to carbon atoms 3 and 4 (chain numbered
in direction which gives lowest numbers).
Ouestion
What are the lUPAC names of A and B? (Work on the reactions of these
compounds was published in the Journal of the American Chemical
Society in 1952.)
CH 3
CH 3
I
I
CH3-CH2-?-CHz-CH2-CH3
CH -C-CH-CH
3 I I 3
A CH 3 B CH 3 CH 3
~ C23 if your answers are correct; otherwise C22.
Optional
C22
CH 3
1 2 I 4 5 6
CH 3 - CHz- 7-CHz- CHz- CH 3
A CH 3 3,3-dimethylhexane
CI
CHz- CHz- CH 3
1 2 I 4 5 6
CH 3 - CHz-?-
CI
3,3-dichlorohexane

Programmed sections
55
~ C23
The name of A is essentially similar to that of 3,3-dichlorohexane. The
two methyl groups, which do not form part of the longest continuous
chain (six carbon atoms) are considered as substituents. In the same way
the name ofB (see C2l) is 2,2,3-trimethylbutane.
Answer to C20
3 4 567
CH 3 -CH -CHz-CH -CHz-CH 3 : 3,5-dimethylheptane.
I 1 I
CHz-CH 3 CH 3
~ C21
Note
The above compound is easier to name if the longest continuous carbon
chain is written horizontally
1 2 3 4 567
CH -CH -CH-CH -CH-CH -CH
3 2 I 2 I 2 3
Answer to C21
CH 3 CH 3
CH 3
1 2 145 6
CH 3 -CH 2 -C-CH 2 -CH 2 -CH 3 : 3,3-dimethylhexane.
I
A CH 3
CH 3
1 I 3 4
CH 3 -C--CH -CH 3 : 2,2,3-trimethylbutane.
I
I
B CH 3 CH 3
~ C23 if your answers are correct; otherwise C22.

56 Programmed sections
C23
Structural formula of 2,2,4-trimethylpentane
Branched chain alkanes generally have better combustion characteristics than unbranched
alkanes. For instance, 2,2,4-trimethylpentane (molecular formula CSHlS) has a much
smaller tendency to cause 'knocking' in car engines than its unbranched isomer, octane,
CH3CH2CH2CH2CH2CH2CH2CH3' For this reason 2,2,4-trimethylpentane, rather than
octane, was chosen as the standard substance for defining the 'octane' rating of different
grades of petrol. (The octane number of this branched alkane is 100.)
Question
What is the structural formula of2,2,4-trimethylpentane?
»»))0-0+ C25 if your answer is correct; otherwise C24.
Optional
: ; ; :
i 2,2,4-~rimethy~pentane i
: c: b : a :
~ ~ t ~
a Continuous chain of five carbon atoms.
1 Z 345
C-C-C-C-C
C24
b Three - CH 3 groups present.
CH 3
1 I 345
c Position ofCH 3 groups indicated: C-C-C-C-C.
I
CH 3 CH 3
I
)~ C25
CH 3
I
Completing the formula CH 3 - C- CHz - CH - CH 3 •
I
CH 3 CH 3
I

Programmed sections
57
C25
Branched chloroalkanes and alcohols
These compounds are named by slightly different methods, because the
chloro functional group is shown by a prefix, while a suffix is used for the
hydroxyl group.
4 3 2 1
CH-CH-CH-CH
3 I I 3
CH 3 CI
2-chloro- 3-methylbutane
Named as a substituted butane. Prefixes
chloro- and methyl- are arranged in
alphabetic order, smallest number first.
4 3 2 1
CH-CH-CH
-CH OH
3 I 2 2
CH 3
3-methylbutan-l-ol
Named as a substituted butan-I-ol.
(Note. 2-methylbutan-4-o1 is not
correct.)
Study the above table before attempting the questions on the next page.
These questions also revise a number of points mentioned earlier.
Answer to C23
CH 3
I
2,2,4-trimethylpentane: CH 3 -C-CH 2 -CH -CH 3 •
I
CH 3 CH 3
}))))-+ C25 if your answer is correct; otherwise C24.
I

58 Programmed sections
Questions
CH 3
I
1 The systematic name of CH 3 - C - CI is:
I
CH 3
A l-chloro-l, I, l-trimethylmethane
B l-chloro-l,l-dimethylethane
c 2-methyl-2-chloropropane
D 2-chloro-2-methylpropane
E 2,2-chloromethylpropane.
2 The systematic name of CH 3 -
CH 3
I
C-- CH -CH 2
I I
CH 3 CH 3
-CH 2 0H is:
A 3,4,4"-trimethylpentanol
B 2,2,3-trimethylpentan-5-o1
c 3,4,4-trimethylpentan-I-ol
D 3,4,4-methylpentan-I-ol.
»>~ C26
Choose the correct term in each case. Attempt to state why the other
names are incorrect. (Read C20, C21, and examine the examples given
at the beginning of this subsection, C25, if you have any difficulties.)

Programmed
sections
59
Answers
to C25
1 The correct name is 2-chloro-2-methylpropane, D. (Note. The formula
can be written as CH 3 -
CH 3
I
C-CH 3
I
CI
emphasizing the continuous chain
of three carbon atoms.)
Incorrect names
A and B Methane and ethane are wrong (chain of three carbon atoms).
c Me thy 1-and chloro- should be in alphabetic order.
E Substituents should be numbered separately (see B2l).
2 The correct name is 3,4,4-trimethylpentan-l-ol, c.
CH 3
(Note.
5 I 3 Z 1
CH 3 -C--CH-CH 2 -CHzOH.)
I
I
CH 3 CH 3
Incorrect names
A Position of hydroxyl group (on carbon atom 1) not shown.
B Chain numbered in the wrong direction.
D Three methyl groups present, hence trimethyl.
)))))-+ C26

60 Programmed sections
C26
General information provided by systematic names
Information about functional groups, number of carbon atoms, and so
on, can often be deduced from names of compounds without writing
out a full structural formula.
1 Which of the following contain one or more " C= C/
groups?
/ ~
dodecane, hexane-l ,2,3-triol, 5-nitrohept-l-ene, cydohexa-l ,4-diene,
3-methylbutan-l-ol
Questions
2 Which of the following contain a total of six carbon atoms per molecule?
cydohexene, octa-l,3,7-triene, 2,3-dibromobutane, 2,3-dimethylbutane,
3-methylpentan-I-ol, 2-methylhex-I-ene
3 Which functional groups are present in the following compounds?
I-bromobut-2-ene, 2-methylbutan-l-ol, 2-iodo-2-methylbutane
»~~ C27
C27
Examples of additional rules
Additional rules to the ones we have met so far are necessary to name
more complex compounds. The examples given below illustrate some
of these.
1 2 3
CH 2 =CH-CH 2 Br 3-bromoprop-l-ene (not l-bromoprop-3-ene)
2-ethylpentan-l-ol. (The longest continuous
chain containing the hydroxyl group is numbered
as shown.)
It is not generally necessary to remember all the rules in detail; reference
books can be consulted. (See also 4.8 in Chapter 4.) In any case it is often
fairly simple to deduce structural formulae from names given in the
chemical literature without an extensive knowledge of all the rules.
An example of this is given in the optional question on the next page.

Programmed sections
61
Optional question
2-Ethylhexane-l,2-diol is an effective insect repellent. What is the
structural formula of this compound? (The ethyl group is:
CH 3 CH 2 -·)
»>'~
C28
Answers to C26
1 5-nitrohept-l-ene, cyclohexa-l ,4-diene. (The suffix -ene indicates a
double bond between carbon atoms, -diene two such bonds.)
2 Cyclohexene, 2,3-dimethylbutane, and 3-methylpentan-l-ol.
3 I-bromobut-2-ene: Br- and " C=C /
2-methylbutan-l-ol: -OH
/ "
~ C27
2-iodo-2-methylbutane: - 1.
Answer to C27 6 5 4 3 2 1
2-ethylhexane-1 ,3-diol: CH 3 - CH 2 - CH 2 - CH - CH - CH 2 - OH.
~ C28
I
OH CH 2 CH 3
Note
The compound is named as a substituted hexane, even though the
longest carbon chain (including the ethyl group) contains seven carbon
atoms. In this case the longest chain containing the hydroxyl group is
chosen as the basis for the name of the compound. It is not essential to
be aware of this rule in order to deduce the formula from the name of
the compound.
I

62 Programmed sections
C28
Summary
1 Organic compounds are classified into different series, each of which is
characterized by a particular functional group. The systematic name of a
compound shows which functional group is present. The prefix chloroindicates
a halogen substituent, the suffix -01 a hydroxyl group (ethanol,
CH 3 CH 2 0H),
"" /
the suffix -ene a C= C group (ethene, CH 2 =CH 2 ),
/ ''''-
the suffix -yne a -C=C- group (ethyne, CH=CH). See CI, C7,
and C14.
2 Compounds with the same molecular formula but different structural
formulae are called structural isomers (see C8, CIO, and C19 for
examples).
3 IUPAC names of alcohols, Junctional group - OH
butan:-l-jol i
a ! c!b
..
: : : :
a four carbon atoms C-C-C-C.
b hydroxyl group.
e hydroxyl group linked to carbon atom I,
4 3 2 1
C-C-C-C-OH (atoms numbered so that the
-OH group is linked to the carbon atom with the lowest
possible number).
butane-l,2-diol
CH 3 CH 2 CHCH 2 0H
I
OH
Two hydroxyl groups indicated by suffix -dial.
Note. Butan¢-l-ol, but butane-l,2-dioI.
See C2 to C6 (detailed tables in C2 and C3).

Programmed sections
63
"" /
4 IUP AC names of alkenes,functional group c= C
/ '"
pent-2-ene penta-l,3-diene The chain is numbered
5 4 3 2 1 1 2 3 4 5 to give the lowest
CH 3 CH 2 CH=CHCH 3 CH 2 =CH-CH=CH-CH 3 possible number. A
single number is
Note. pent;i-2-ene, but penta-l ,3-diene sufficient to show the
presence of one double
bond between two
carbon atoms.
See C7 to C13 (detailed tables in C8 and CII).
5 IUP AC names of cycloalkanes and related compounds
Cyclic compounds are indicated by the prefix cyclo-, for instance:
CH 2 -CH
,,/
2
CH 2
cyclopropane
CH 2 -CH 2
I
CH 2 -CHCI
chlorocyclo butane
See Cl6 to Cl8 (tables in Cl6 and CI7).
I
CH=CH
/ "-
C~ /CH 2
CH 2
cyclopentene
6 IUPAC names of branched chain alkanes
Branched chain alkanes are named on the basis of the longest
unbranched (continuous) chain; any other groups, such as methyl,
CH 3 -, are indicated by means ofa prefix.
1 2345678
CH -CH -CH-CH-CH -CH -CH -CH
3 2
1
I 2223
CH 3 CH 3
3,4-dimethyloctane
The chain is numbered to
give the lowest possible
numbers. It is important to
choose the longest chain
correctly.
See Cl9 to C24 (tables in Cl9 and C21).

64 Programmed sections
7 Branched chain chloroalkanes and alcohols
4 3 2 1
CH -CH-CH-CH
3 I I 3
CH 3 CI
2-chloro-3- methylbutane
4 3 2 1
CH -CH-CH -CH OH
3 I 2 2
CH 3
3-methylbutan-l-ol
See C25.
8 Further rules are required to name complex compounds. It is not
generally essential to memorize these. Structural formulae can often be
deduced from names witho_utextensive knowledge of all rules. Some
information can be obtained from a name without writing a structural
formula; for instance the functional group. (See C26 and C27.)
9 The IUPAC name of a compound can be translated unambiguously into
a structural formula. It is important to be able to do this correctly.
(See C2, C4, C13, CIS, CI6, CI7, C23, and C24 for examples.)
Note
You may find it useful to read sections 4.2 to 4.5 in Chapter 4, at this
stage.
»}J~
Review problems, Chapter 2,2.2. Additional optional problems are
in 2.3.

Programmed sections
65
Section D
Sections Band C dealt mainly with alkanes, halogenoalkanes, alkenes,
cyc1oalkanes, and alcohols. This section introduces a number of other
series; further details are given in Chapter 4 (see for instance,
4.8a-4.8i).
Alkynes
Ethyne, H -C-C- H, generally called acetylene, is the most
important member of the alkyne series. The table on the next page
summarizes systematic names of alkynes.
Acetylene is generally made from calcium carbide, CaC z (manufactured from coke) or
from natural gas. Handling acetylene presents considerable hazards, but during the
Second World War, W. Reppe and others developed special methods for handling
acetylene safely, so that it is now used on a very large scale to manufacture solvents, and
chemicals which are converted to synthetic fibres (for example, Acrilan), rubber
(Neoprene), and resins (polyvinyl acetate).
D1

66 Programmed sections
Names of alkynes
The suffix -yne shows the presence of the -C=C- functional group.
The rules for naming alkynes are similar to those for alkenes (see C8).
For example:
CH=CH
:............. :.............. :
ethyne
1 .....•....... ~ .............. j
The name acetylene is frequently
used instead of the systematic one,
ethyne.
CH 3 C=CH
...... ••••• 1'•••••••••••••• :
propyne
:............ :............... :
Methylacetylene is sometimes
used.
5 4 3 2 1
CH 3 CHCH 2 C=CH 4-methylpent-I-yne Compare: CH 3 CHCH 2 CH=CH 2
I
I
CH 3 CH 3
4-methylpent-I-ene
Note
Acetylene is not a systematic name. The ending -ene does not indicate a
" / bond in this case.
c=c
/ "'-
Ouestion
Give the structural formulae of but-l-yne and but-2-yne.
»>>>-+ D2
Benzene
Benzene is the most important arene (aromatic hydrocarbon).
02
In 1965, the total value of United States benzene production was over 200 million dollars;
this is expected to rise to 300 million dollars by 1970. (For comparison, the value of the
1965 United States production of sulphuric acid, one of the basic raw materials of
the chemical and allied industries, was approximately 625 million dollars.)
Benzene, C 6 H 6 , is a compound of considerable theoretical interest. It was first isolated by
Michael Faraday in 1825; F. A. Kekule suggested a cyclic formula in 1865 (see A below).
B is a simplified version of this formula. It was soon realized that Kekule's original
formula was inadequate to represent the structure of benzene. Benzene is not simply
'cyclohexa-l,3,5-triene' as indicated by formula A. Kekule himself made an alternative
suggestion in 1872. The formula of benzene is discussed further in 4.1b.

Programmed sections 67
Figure 8
Benzene, C 6H6 : skeletal and space-filling models.
Experimental evidence derived from the physical and chemical
properties ofbenzene shows that the benzene molecule is symmetrical;
all six carbon atoms are completely equivalent (see 4.1b for further
details). Formula C, or the simplified form D (see below), is generally
used. Figure 8 shows models of the benzene molecule. Note that the
molecule is 'flat' and compare its shape with that of cyclohexane, C18.
Benzene, C 6H6
H
C
HC-:? '-~H
I
I
HC,,::- /CH
C
H
H
0
C
0
HrQ?H
HC" yCH
C
H
A B C D
Answer to D1
but-l-yne: CH 3CHzC
CH
)))))-00+ D2
Note
1. The carbon chain is numbered as shown.
43 Z 1 43 Z 1
CH 3CHz-C-CH CH 3-C-C-CH3
2. Compare but-l-ene, CH 3CHzCH=CHz and
but-2-ene, CH 3CH=CHCH3 .

68 Programmed sections
Systematic names of benzene derivatives
Suitable prefixes are used in many cases particularly for
halogenobenzenes and alkyl benzenes ; see chlorobenzene and
propylbenzene below.
Chlorobenzene, C6HsCI
yl
6
HC" yCH HC" yCH
C
H?O?H
C
H
Propylbcnzenc, C6HsCH2CH2CH3
C
HCOCH
I I
yH2CH2CH3
C
H
,6CH
'CH'
Note. The benzene ring is symmetrical. Replacing anyone of the
hydrogen atoms by chlorine leads to the same compound. The name of
C 6 HsCI is therefore chlorobenzene, not l-chlorobenzene (see 4.4).
Study the above formulae of benzene (page 67), chlorobenzene, and
propylbenzene, and then attempt the questions below.
ouet~~at
are the names of6and6:H3
2 Write the formulae of bromo benzene and butylbenzene.
3 The formula of nitro ethane is CH 3 CH 2 N0 2 . What is the formula of
nitro benzene?
Names and formulae of some alkyl groups are given below (see 4.6b and
4.6c for a more extensive list of names of different groups).
Examples of alkyl groups
Ethyl
Propyl
Pentyl
Dodecyl
CH 3 CH2-
CH 3 CH2CH2-
CH 3 (CH2hCH2-
CHiCH2)10CH2-
)}ll~ D3 if you need help; otherwise D4.

Programmed sections 69
Answers
to D2
16fluorobenzenc
o;CH:thYlbenZene
Br
2 bromobcnzene6(C6H,Br)
CHzCHzCHzCH 3
butylbenzene6(C6H,CH2CH2CH2CH3)
NOz
3 nitrobenzene
6(C6H,N02)
~ D4
Note
Check against the formulae of chlorobenzene and propylbenzene in D2
if your answers to 2 and 3 showed the carbon and hydrogen atoms in the
benzene ring.

70 Programmed sections
D3
Optional
orepresents a benzene ring, C 6 H 6 ; see formula D in D2.
F
In6one hydrogen atom of benzene has been replaced by fluorine
to give C 6 HsF
(fluorobenzene).
Butylbenzene is a compound in which one hydrogen atom of benzene is
replaced by a butyl group, CH 3 CH 2 CH 2 CH 2 -. The formula is
C6HsCH2CH2CH2CH3OCH2CH2CH3.
Attempt the questions in D2.
D4
C 6 HsCH 2 CH 3 is generally named ethylbenzene (a substituted benzene
derivative). It can also be named phenylethane (substituted ethane); one
hydrogen atom in ethane is replaced by a phenyl group, C 6 Hs-.
HTO~~~H
HC"
I
6
C
;;.--CH
C
H
ethylbenzene, C 6 H s CH 2 CH 3
(phenylethane)
Ouestion
The compound CH 3 C=CH is commonly named methylacetylene (see
Dl). What is the formula of phenyl acetylene?
~)>>-+ D5

Programmed sections
71
Trivial names of benzene derivatives
Many derivatives of benzene are almost exclusively known by their
trivial names. This is due in part to the enormous industrial importance
of these compounds. An example is vinylbenzene, C 6 HsCH==CHz.
(The vinyl group is CH 2 =CH -.) This compound, which could also be
named phenylethylene or phenylethene, is generally called styrene.
D5
Styrene is used to manufacture polystyrene and, in combination with buta-l ,3-diene,
synthetic rubber. About one third of the benzene production of the United States is used to
manufacture styrene:
ethylene
) C 6 H s CH 2 CH 3
ethylbenzene
-Hz)
(dehydrogenation)
C 6 H s CH=CH 2
vinylbenzene (styrene)
The trivial names of three important benzene derivatives are given
on the next page. You will find it useful to memorize them.
Answer to D4 C=CH
phenylacetylene oor
C6HsC=CH
)))))-+ D5

72 Programmed sections
Commonly used names of benzene derivatives
toluene phenol styrene
C 6 HsCH 3 C 6 HsOH C 6 HsCH=CH 2
6
OH
6
6CH,
Notes
1. Phenol is not a systematic name, but the suffix -01 does indicate a
hydroxyl group.
2. The formula of phenol is C 6 H s OH, the phenyl group is C 6 H s -.
3. Systematic names of benzene derivatives are discussed in 4.8h, and
trivial names in 4.10j.
Question
Write out the formulae of phenol and styrene showing all the hydrogen
and carbon atoms present.
>l»>-+
D6 (see formulae of chloro benzene and propylbenzene in D2 if you
need help.)
The question below revises a few points covered earlier. Read the
summaries to Sections Band C (B23 and C28) and also Dl if you have
any difficulties.
Ouestion
Give the formulae of l,l-dibromoethane, 2,2-dimethylbutan-l-ol,
4-chloropent-I-ene, and 4-ethylhex-l-yne. Indicate the functional
groups present in each of these compounds.
)}»)-+ D7
D6

Programmed sections
73
Answer to 05
OH
I
C
/ "'-
HCQCH
phenol I I
HC
''''- /
CH
CH
CH=CHz
I
C
/ "'-
HCQCH
styrene I I
HC
'",- /
CH
CH
~ D6
Answer to D6
Name Formula Functional group
l,l-dibromoethane CH 3 CHBr 2 -Br
CH 3
I
2,2-dimethylbutan-l-ol CH 3 CH 2 -C-CH 2 OH -OH
I
CH 3
5 4 3 2 1
'" /
4-chloropent-l-ene CH 3 CHCICH 2 CH=CH 2 -Cl, C=C
/
"\
6 5 4 3 2 1
4-ethylhex-l-yne CH 3 CH 2 CHCH 2 C=CH -C=C-
I
CH 2 CH 3
)))))--+ D7

74 Programmed sections
D7
Aldehydes, carboxylic acids, and acid chlorides -
functional groups, formulae, and systematic names
The functional groups given in the answer to D6 can be divided into two
classes:
1
2
Groups which contain only atoms other than carbon: - Br, - CI,
-OR.
Groups which contain only carbon atoms:
'" /
/ '"
C=C ,-C-C-.
Functional groups in many series of compounds contain carbon as well
as atoms of other elements such as oxygen and chlorine. A few examples
of functional groups and compounds of this type are given below. (A
more extensive list is given in 4.7a-4.7c.)
Functional group Name of relevant Example of compound
series of
expanded condensed compounds
formula formula formula name
0
~
-C -CHO aldehydes CH 3 CH 2 CH 2 CHO butanal
'",
H
0
~
-C -C0 2 H carboxylic acids CH 3 CH 2 CH 2 C0 2 H butanoic
(or-COOH) acid
'" OH
0
~
-C -COCl acid chlorides CH 3 CH 2 CH 2 COCl butanoyl
chloride
CI
'"

Programmed sections
75
Note
1. Butanal, CH3CH2CH2CHO, butanoic acid, CH3CH2CH2C02H,
and butanoyl chloride, CH3CH2CH2COCI, each contain a total of four
carbon atoms (including the carbon which is part of the functional
group).
2. The suffix -al shows that an aldehyde group -CHO is present;
-oic acid indicates -C0 2 H; -oyl chloride indicates -COCl.
3. Numbering such as butan-I-al is not required (see 4.4).
4. Condensed formulae must be written as shown in the table above, for
example CH3CH 2 CH 2 CHO, not CH3CH 2 CH 2 COH, for the
aldehyde, butanal.
5. Systematic names of aldehydes, carboxylic acids, and their
derivatives are discussed further in 4.8b and 4.8d.
Study the table opposite and notes above before attempting the
questions below.
Ouestions
1 CH3CH2CHO is named ethanol/ethanal/propanol/propanal/none of
these.
2 The formula of hexanoic acid is CH3(CH2)4C02H/CH3(CH2)SC02H/
neither.
3 The formula of ethanoyl chloride is CH3CH 2 COCI/CH3COCI/neither.
Choose the correct term in each case.
)))))-+ D I0 if all your answers are correct; otherwise D9. Read D8 if you need
help with the above questions.
Answers to D7
1 CH3CH2CHO: propanal.
3 ethanoyl chloride: CH3COCl.
~ D 10 if all your answers are correct; otherwise D9.

76 Programmed sections
Optional
Look at the table in D7. Note two points in particular:
D8
1 Functional groups and the corresponding suffixes.
I-ai'
-CHO
-oie acid: -COzH
-oyl chloride:
-COcl
2 The main 'stem' of the name includes the carbon atom of the functional
group.
Formula CH 3 CHO CH 3 CHzCOzH CH 3 CHzCHzCOCI
Name ethanal propanoic acid butanoyl chloride
Number of
carbon atoms two three four
Attempt the questions in D7.
Optional
1 CH 3 CH 2 CHO
: : ;
i propa~al i
: a :b:
L ~ ~
a propan Total of three carbon atoms including the carbon atom of the
functional group.
b -al Aldehyde group, -CHO, present.
D9
~
(Note. -at shows -C.
""
o
H
,aldehyde group; -ot shows hydroxyl group.)

Programmed sections
77
: : , :
! hexa~oic acid !
: a: b :
~ t i
a hexall Chain of six carbon atoms, including the carbon atom in
-COzH.
b -oic acid -C0 2 H, carboxyl group present.
: : :
: ethan,~yl chloride !
: a: b :
1 ) 1
a ethall Total of two carbon atoms.
b -oyl chloride - COCI, acid chloride group, present.
Note
In the formulae below details of the functional groups are given.
propanal
~ DIO
hexanoic acid
o
~
CH-C
3 '"
Cl
ethanoyl chloride

78 Programmed sections
Ouestions
1 Write the structural formulae of pentanal, pentanoic acid, and
pentanoyl chloride.
D10
2 Which functional groups are present in octanal, ethanol, propyne, and
propanoic acid?
»)~ DIL (Read D9, and if necessary D8, if you require help with question 1.)
D11
Aldehydes, carboxylic acids, and acid chlorides - trivial names
Trivial names are widely used for some aldehydes and carboxylic acids.
The systematic names (bracketed in the examples given below) are
relatively rarely used in these cases. Yoli will find it useful to memorize
these commonly used names. (For a further list see 4.10e, 4.10g, and
4,IOh.)
HCHO
formaldehyde (methanal)
CH 3 CHO
acetaldehyde (ethanal)
HC0 2 H
formic acid (methanoic acid)
CH 3 C0 2 H
acetic acid (ethanoic acid)
Ouestion
Note also. CH 3 COCI acetyl chloride (ethanoyl chloride).
~
The expanded structural formula of formaldehyde is H - C .
'" H
Write expanded formulae for formic acid, acetaldehyde, acetic acid,
and acetyl chloride. (Answer on page 81.)
o
>>>It-+
D12. (See the table in D7 if you need help.)

Programmed sections
79
Answers to D 1 0
1 pentanal: CH3CHzCHzCHzCHO
pentanoic acid: CH3CHzCHzCHzCOzH
pentanoyl chloride: CH3CHzCHzCHzCOCl.
Note
You may have written expanded formulae, such as
o
~
CH3CHzCHzCHzC
''''
H
H
ethanol: -OR (hydroxyl)
propyne: -C-Co
~
propanoic acid: -C or -COzH (carboxyl).
2 Functional groups
o
~
octanal: -C or -CHO (aldehyde)
"'-
"'-
OR
Note
Formulae for reference: CH3(CHz)6CHO,
CH 3 C CH, CH3CHzCOzH.
CH3CHzOH,
~ Dll

80 Programmed sections
012
Formaldehyde is manufactured by the oxidation of methanol. The reaction between
formaldehyde and phenol, first investigated by Bayer in 1872, was developed by Baekeland
in 1909 into a process for the preparation of phenol-formaldehyde (Bakelite) resins. Over
700 million pounds of these resins were manufactured in the United States in 1963, in spite
of competition from newly developed plastics.
Ouestion
Give the formulae of methanol, formaldehyde, and phenol.
»)~D-+
D13
D13
Substituted carboxylic acids and aldehydes
Nitromethane, CH 3 N0 2 , now available commercially, was first made from nitroacetic
acid. Chloroacetic acid is the most important substituted acetic acid used to manufacture
pharmaceutical chemicals and selective weedkillers.
Note how substituted acetic acids are named
Ouestion
The formula of chloroacetic acid is CICH z COzHjCH 3 COCl.
the correct term giving reasons.
)m~
D14
Choose
D14
Trifluoroacetic acid is a useful laboratory reagent. Trichloroacetaldehyde, sometimes
called chloral, is of commercial importance. It is used in the manufacture of the insecticide
DDT. A hydrated form of this compound, chloral hydrate, has been used as a
quick-acting sedative medicine since 1869.
Question
What are the formulae oftrifluoroacetic
(Answer on page 83.)
acid and trichloroacetaldehyde?
)})J~
DI5

Programmed sections 81
Answer to D 11
o
formic acid: H -
~
~
C acetaldehyde: CH 3 -
'"
H
o
acetic acid: CH 3 -
Note
~ Dl2
~
C
"
o
OH
acetyl chloride: CH 3 -C
C
.'"
H
o
~
''''CI
You may have written fully expanded formulae, for instance
H 0
I ~
H - C- C for acetaldehyde.
I
H
'"
H
Answer to D 1 2
methanol: CH 3 0H
o~H
formaldehyde: HCHO or H-C
~
o
~ Dl3
Note
Check your answers carefully. Methanol contains a hydroxyl group.
The systematic name of formaldehyde is methanal. See D5 for formula
of phenol.
Answer to D 1 3
Chloroacetic acid: CICH 2 C0 2 H.-The functional group present is the
carboxyl group, - C0 2 H, characteristic of carboxylic acids.
CH 3 COCl contains the -COCI functional group characteristic of
acid chlorides. (The name ofCH 3 COCI is acetyl chloride or ethanoyl
chloride.)
~ D14

82 Programmed sections
Condensed
form u Iae
D15
Care is needed in writing condensed formulae correctly. For instance,
the condensed formula of formaldehyde (methanal) is HCHO, not
HCOH. HCOH suggests a hydroxyl group, formaldehyde contains the
o
aldehyde group -
~
C
""
.
H
Ouestion
Choose the correct condensed formula for compounds A to D below.
Give the names of A to D. (Condensed formulae are discussed further in
4.1c.)
0
~
A CH 3 CHzC CH 3 CHzCOH / CH 3 CHzCHO
'" H
H
I
B CH 3 CHz-C-CH 3 CH 3 CHzCH(OH)CH 3 / CH 3 CHzCHCH 3 OH
I
OH
~
°
C CH -C CH 3 COzH / CH 3 CHOz
3 "-
~
OH
°
D CH -C CH 3 CCIO / CH 3 COCl
3 '"
Cl
J)))ooo+ D 16
Note
Examples of further series of compounds, such as ketones and amines,
and rules for naming them are in Chapter 4, 4.8.

Programmed sections
83
Answer to D 1 4
F 0
I ~
trifluoroacetic acid: F- C- C or CF 3 C0 2 H
I '"
F
OH
Cl 0
I ~
trichloroacetaldehyde: Cl- C - C or CCl 3 CHO
I '"
Cl
H
)))))-+ DI5
Answer to D 1 5
Formula
Name
systematic
alternative
A CH 3 CHzCHO propanal
B CH 3 CHzCH(OH)CH 3 butan-2-ol
C CH 3 COzH ethanoic acid acetic acid
D CH 3 COCl ethanoyl chloride acetyl chloride
~ D16
Notes
1. The bracket used in the formula of B may have been new to you, but
it should have been obvious that CH 3 CH 2 CHCH 3 0H cannot be
correct.
2. Check your answers carefully, particularly propanal and butan-2-ol.

84 Programmed sections
D16
Summary
1 Alkynes contain the -C=C- group; The presence of this group is
shown by the suffix -yne. IUPAC rules for naming alkynes are similar
to those for alkenes (see C8).
CH3CH2C=CH
but-l-yne
CH3CH2CH=CH2
but-l-ene
Trivial names are commonly used for some alkynes; particularly
acetylene, rather than ethyne, for HC=CH (see Dl).
2 The formula of benzene, C 6 H 6 , can be written in a number of ways, for
instance C and D below (see D2 and 4.1b for further points about this
compound).
H
C
RCO"":::~CR
I I
HC", :;/CH
C
H
c
o
D
3 Systematic names of benzene derivatives
Prefixes are used for halogenobenzenes and alkylbenzenes such as
ethylbenzene. An alternative name for ethylbenzene, C 6 HsCH 2 CH 3 ,
is phenyl ethane (see D2 to D4).
CI
I
C
HCO~ ~CH
I I
HC", :;/CH
C
H
chloro benzene
C 6 H s CI
propylbenzene
C6HsCH2CH2CH3
nitro benzene
C 6 H s N0 2
phenyl group
C 6 H s -
(Further details of systematic names of benzene derivatives are in 4.8h.)

Programmed sections
85
4 Trivial names of benzene derivatives
Some of the most important benzene derivatives are almost exclusjvely
known by their trivial names (see 05 and 4.10j).
C 6 HsCH=CH 2
styrene (vinyl benzene)
5 Systematic names of aldehydes, carboxylic acids, and acid chlorides
These compounds contain carbon as well as atoms of other elements in
their functional group (see D7 to DIO).
Functional group -CHO -COzH -COCI
Series aldehydes carboxylic acids acid chlorides
Example:
name butanal butanoic acid butanoyl chloride
formula CH 3 CH z CH z CHO CH 3 CHzCHzCOzH CH 3 CH z CH z COCl
Detailed example:
o
~
CH 3 (CH 2 hC
'"
OR
; : :
! penta~oic acid 1
! a j b j
L } I
a pentan Chain of five carbon atoms, including the carbon atom of the
C0 2 H functional group.
b -oie acid -C0 2 H (carboxyl group) present.
Notes
1. The suffix -01 denotes an -OH group, -al an aldehyde (-CHO)
group.
2. See 4.8b and 4.8d for further details of systematic names of these
compounds.

86 Programmed sections
6 Trivial names of aldehydes, carboxylic acids, and acid chlorides
The systematic names of some compounds (shown in brackets below)
are rarely used (see D 11 and D 12, and also 4.1Oe,4.1Og,and 4.1Oh).
HCHO formaldehyde (methanal) CH 3 CHO acetaldehyde (ethanal)
HC0 2 H formic acid (methanoic acid) CH 3 C0 2 H acetic acid (ethanoic acid)
CH 3 COCI acetyl chloride (ethanoyl chloride)
7 Substituted aldehydes and carboxylic acids are named as shown below
(see Dl3 and DI4).
CICH 2 C0 2 H C 6 H s CH 2 C0 2 H CCI 3 CHO
chloroacetic acid phenylacetic acid trichl 0 roaceta ldeh yd e
Note
CICHzCOzH, chloroacetic acid; CH 3 COCI, acetyl chloride.
8 Condensed formulae of aldehydes, acids, and so forth, must be written
with care. For instance HCHO, not HCOH, for formaldehyde.
0 0 0
~ ~ ~
-c -CHO -C -C0 2 H -c -coel
'"
'" H OH '" CI
aldehyde group carboxyl group acid chloride group
(See DIS, and also 4.Ic.)
9 Examples of further series of compounds are given in Chapter 4,4.8.
))~ Review problems, Chapter 2, 2.4. These also review parts of Sections B
and C. (Summaries of these sections are in B23 and C28.) Further
optional problems are in 2.5.

87
Chapter 2
Review problems
Problems in 2.1 relate mainly to Section B.
Problems in 2.2 relate mainly to Section C.
Problems in 2.4 relate to Sections B to D.
More difficult optional problems are included in 2.3 and 2.5.
Answers are given in Chapter 5, sections 5.1 to 5.5.
Checking your answers carefully will help you to decide whether you
need to work through the additional exercises in Chapter 3, sections
3.2 to 3.4.
Note
Information about the properties of some of the compounds, or of
general scientific and technological interest, is included in smaller type
in 2.1 to 2.5, and 5.1 to 5.5. Read this if you wish.
2.1 Review of Section B
Note
You should at this stage be able to interpret condensed structural
formulae but may have some difficulties in writing these down correctly.
Expanded structural formulae can be given as answers to problems
3b and 6. You may find it helpful to read B22 again. Structural formulae
are also discussed in Chapter 4, 4.1.

88 Review problems
1 The boiling points of alkanes increase with increasing chain length.
(Methane boils at -162°C, octane at 126°C, see figure 9.) Arrange the
following in order of ascending boiling points: pentane, propane,
butane, hexane, ethane.
~ .......
200 E
'0 c.
Ol
,§
'0 0
al
100 0
0
0 •
0
-100
•
0
2 3 4 5 6 7 8
Number of carbon atoms in chain
Figure 9
Boiling points of alkanes.
After Noller, C. R. (1965) Chemistry of organic compounds, Saunders
2 Give the IUPAC names ofCH 3 CH 2 Cl and CHCI 3 •
Some chloroalkanes are manufactured in very large quantities: for example, the United
States production ofCH 3 CH 2 CI in 1962 was approximately 300 million kg; production
of CHCl 3 was 50 million kg in the same year.
3 Compounds which have one fluorine atom on each of two adjacent
carbon atoms are highly reactive. Compounds which have two fluorine
atoms on the same carbon are extremely inert to most chemical
reagents.
a. Which is more reactive, 1,I-difluoroethane or 1,2-difluoroethane?
b. Give the structural formulae of these two compounds.
Many chloroalkanes are used in industry as solvents. Some of these -6olventsare highly
poisonous, but in general this is dependent on the structure of the particular compound.
CHCI 2 CHCI 2 , for instance, is highly toxic and corrodes metals in the presence of
moisture. CH 3 CCI 3 , on the other hand, has low toxicity and is incorporated into some
mixtures used for spray-cleaning of railway equipment.

Review problems
89
5 Give the IUPAC names of
A CH 2 CICH 2 CH 2 CI
B CH 3 CHBrCH 2 CH 2 CH 2 Br
C CH 2 CICH 2 CH 2 Br.
Many halogenoalkanes, which are difficult to prepare and purify by laboratory methods,
are now available commercially; for instance: A CH 2 ClCH 2 CH 2 Cl,
B CH 3 CHBrCH 2 CH 2 CH 2 Br, and c CH 2 ClCH 2 CH 2 Br. Some of these compounds are
useful for various commercial preparations. For example, CH 2 ClCH 2 CH 2 Br is used in the
manufacture of cyclopropane, used as an anaesthetic (see Cl6 for formula of
cyclopropane) .
6 Many organic compounds containing fluorine are commercially
important. Examples are given below.
Name
Use
Dichlorodifl.uoromethane
Bromotrifluoromethane
I-Bromo-1-chloro-2,2,2-trifluoroethane
refrigerant; aerosol sprays
low toxicity fire extinguisher
surgical operations (anaesthetic)
Write structural formulae for the compounds given in the above table.
Fluorine compounds are important products of the chemical industry, particularly
Teflon, a high molecular weight polymer containing only carbon and fluorine. This
polymer is chemically inert (it is only attacked by molten alkali metals), and is therefore
extremely useful for coating different sorts of vessels, valves, and containers. Mixtures
containing fluorinated organic compounds have shown some promise as artificial blood
substitutes.
A new method for fluorinating solid carbon-containing materials by direct treatment with
fluorine (reported in Chemical and Engineering News (1970), 48,2, p. 40) reduces the
hazards normally associated with this type of reaction by strict control of temperature and
pressure. Polyethylene, a polymer, containing carbon and hydrogen, can be converted
to Teflon in this way. Graphite yields a white material of great potential value as a
lubricant in aeronautic and space research.
Answers to problems 1 to 6 are in 5.1.

90 Review problems
2.2 Review of Section C
Note
Condensed or expanded structural formulae can be given as answers to
problems 12 and 13 (also problem 16 in 2.3).
'" /
7 Which of the following contain a C=C group? propane, propyne,
propene. / "
8 Which functional groups are present in each of the following?
3-chlorohex-I-ene, cyclobutanol, 2-methylpentane-1 ,3-diol,
hepta-l,3-diene. Which of these compounds contain six carbon atoms
per molecule?
9 Give the IUP AC name of the isomeric compounds, A and B, molecular
formula C 4 H 10 .
CH CH CH CH
322 3
A
isomerization)
The conversion of a compound into an isomeric compound is called isomerization. The
isomerization of unbranched chain alkanes into branched chain isomers is of great
importance in the petroleum industry.
10 What are the IUPAC names of C, D, and E? Decide whether C is an
isomer ofD or E. Give reasons.
B
CH 3 CH 2 CH=CH 2
c D E
11 Give the IUPAC names of the isomeric compounds, F, G, and H.
CH 3
I
CH-C-CH
3 I 3
OH
F G H

Review pro blems
91
12 Write the structural formulae of pentan-2-o1 and pent-2-ene.
Pent-2-ene is the chief product obtained on heating pentan-2-ol with 60 per cent sulphuric
acid at about 90°C.
13 Write the structural formulae of (a) buta-l,3-diene (used in the
manufacture of synthetic rubber), and (b) butane-l,4-diol (used to
manufacture polymers suitable for waterproofing textiles).
Answers to problems 7 to 13 are in 5.2.
2.3 Optional problems, Section C
14 The formula CH 3 CHCH 2 CH=CH 2 represents (a) 4-methylpent-l-ene,
I
CH 3
(b) 4-methylpent-2-ene, (c) neither of these compounds. Choose the
correct term.
The British chemical company, leI, uses a special process for the manufacture of polymers
from 4~methylpent-l-ene. A French process uses a mixture of this compound and its
isomer, 4-methylpent-2-ene. (Reported in Chemical and Engineering News (1966), 44, 46,
p.39.)
15 Alkenes and dienes with unbranched carbon chains react with
hydrogen in the presence of some special catalysts; branched chain
alkenes and dienes generally do not react under these conditions.
In the presence of these 'shape-selective' catalysts (see below), hydrogen
is likely to react with: compound H/compound J/both compounds/
neither compound. Choose the correct term giving reasons. What are
the IUP AC names of Hand J?
CH 3
I
CH==CH-CH==CH 2
H
J
Synthetic 'shape-selective' catalysts have been developed recently (reported in Chemical
and Engineering News (1964), 42,6, p. 45).

92 Review problems
,4 16 What are the structural formulae of the following isomers of
hexadecane? 3-methylpentadecane, 4-propyltridecane, 5-butyldodecane.
(The formula ofhexadecane is CH3(CH2)14CH3' See 4.6a and 4.6b in
Chapter 4 if you need further help.)
The study of the action of bacteria on hydrocarbons and substituted hydrocarbons is
currently an active field of research. It is of importance in the disposal of waste materials
containing detergent, and in the possible production of food from petroleum sources.
Protein foods derived from petroleum may in due course make a significant contribution
to the world's food supply. British Petroleum is likely to be the first oil company to
manufacture proteins for animal feed supplement from hydrocarbons on a commercial
scale.
In general, unbranched chain alkanes are utilized more easily by bacteria than isomeric
branched alkanes. The utilization of hydrocarbons and related compounds by bacteria was
discussed at an international congress in London (reported in Chemistry and Industry
(1964), p. 1532). Examples of alkanes, discussed at this meeting, are hexadecane and some
of its isomers such as 3-methylpentadecane, 4-propyltridecane, and 5-butyldodecane.
Answers to problem 14 to 16 are in 5.3.
2.4 Review of Sections B to D
Note
1. Problems 17 to 22 review points from Sections Band C, as well as
Section D.
2. Condensed or expanded structural formulae can be given as answers
to problem 20.
17 Oxidation of toluene, C 6 HsCH3, yields C 6 HsC02H. C 6 HsCOzH is an
aldehyde/a carboxylic acid/neither. Choose the correct term.

Review problems
93
18 Give the functional groups present in each of the following: decanal,
cyc1opentanol, octa-l ,3-diene, oct-3-yne, 3,3-diethylhexan-I-ol,
acetylene, ethylene.
19 To which series of compounds do each of the following belong?
CH 3 CH z CHO, CH 3 CI, CH 3 C=CH, CH 3 CH=CHCH 2 CH 3 ,
CH 3 CHzOH. (Example. CH 3 CH 3 is an alkane.)
20 Give the structural formula of each of the following: benzene,
CYc1ohexane,cyclohexene, hexanoic acid, acetic acid, hexane-I,3-diol,
bromo benzene, 2,2,3-tribromohexane.
21 a. The formula CH 3 COCI represents: chloroacetic acidj
chloroacetylenejacetyl chloridejchloroacetaldehydejnone of these.
Choose the correct term.
b. The formula CH 3 CH=C=CH z represents: buta-l,2,3-dienej
buta-2,3,4-dienejbuta-l ,2-dienejbuta-3,4-dienejnone of these. Choose
the correct term.
22 This problem deals with the names of a variety of commercially
important organic compounds (see figure 10 on the next page).
Alternative formulae are given for compounds A to E, for instance, for
compound A:

94 Review problems
CH 2=CH-CH=CH2 +- CH 3CH2CH=CH2
R
S
Figure 10
Name A to T in figure 10.
The diagram (figure 10) represents a number of industrial processes. The main raw
materials, such as compounds C, G, N, and P, are obtained chiefly from petroleum
sources. Most of these processes require special catalysts; some are carried out at elevated
temperature and pressure.
Compounds C and G react to form compound D. The process N-+O involves the use'of
carbon monoxide and hydrogen; P-+J is an oxidation in which the carbon chain is broken
into smaller fragments; Q and S combine to give T. You may find it interesting to look up
details ofsome of these in reference books.
Answers to problems 17 to 22 are in 2.4.
2.5 Further optional problems
23 CBr 4 + CH 3(CH2)sCH=CH2 - CH 3(CH2hCHBrCH2CBr3
A B C
Give the IUPAC names of A, B, and c.

Review problems
95
Reactions which lead to an increase in the length of the carbon chain of a compound are of
special interest to organic chemists. When exposed to the light of a mercury arc, a 6 to 1
molar mixture ofA and B reacts, in the absence of oxygen, to give c (reported in the Journal
ofthe American Chemical Society (1947), 69, p. 1105).
24 3,3-dimethylbut-l-ene -+ 3,3-dimethylbutan-2-o1
D
E
Give the structural formulae OfD and E.
The hydration of alkenes to give alcohols is of major importance in the chemical industry
(see 2.4, problem 22, G-+Hand N -+ M). This sort of process is difficult to use in the
laboratory, but a new method, described as'a remarkably rapid and simple way of
preparing pure alcohols from alkenes in yields of 90 to 100 per cent, was reported in the
Journal ofthe American Chemical Society (1967), 89, p. 1522. In this method the alkene is
treated first with a mercury salt in the presence of water and a solvent, then with sodium
hydroxide, and sodium borohydride, NaBH 4 . This, for example, converts D to E.
25 Give the structural formulae ofcycloocta-l,5-diene and
cyclododeca-l,5,9-triene.
Methods of preparation of carbon compounds have made remarkable progress since the
tum of the century. The synthesis of many cyclic compounds, particularly those containing
rings of 8 to 12 carbon atoms, presented considerable difficulties until a few years ago. In
1905, R. Willstatter and his collaborators achieved a difficult four-stage synthesis of
cycloocta-I ,5-diene. They used an expensive starting material which was isolated in small
quantities from the root bark of the pomegranate (reported in the German chemical
journal, Berichte der deutschen chemischen Gesellschaft (1905), 38, p. 1979).
In contrast, an advertisement published in a chemical journal in November 1967
announced: 'Big ring hydrocarbons are going commercial in 1968. Cycloocta-l,5-diene
and cyclododeca-l,5,9-triene will be produced at the rate of 25 million pounds per year.'
(Special types of nylon, Nylon 8 and Nylon 12 respectively, are manufactured from these
compounds.)
26 Willstatter's main aim in the work quoted above was the preparation of
cycloocta-L'Lo.J-tetraene (also available commercially now). He achieved this in 1913
by means of an even more difficult seven-stage synthesis using the same expensive raw
material (reported in Berichte der deutschen chemischen Gesellschaft (1913), 46, p. 517).
Willstatter was interested in this compound, because he wanted to compare its properties
with those of benzene.
Write a structural formula for cycloocta-l,3,5,7-tetraene. Can you see
why Willstatter found this compound ofinterest?

96 Review problems
27 Structural formulae give no direct indication of molecular geometry.
Three-dimensional representations must be used whenever geometric
factors are important. Methane and 2,2-dimethylpropane are sometimes
represented as in figure 11. (See figures 4 (A4) and 13 (3.1) for
illustrations ofmodels of these molecules.)
Figure 11
Three-dimensional representations of methane and 2,2-dimethylpropane.
H
I ----+
dj:~I\"'CH3
CH 2CH3
F
G
Figure 12
In a review ofcertain types of reactions published in Chemical and
Engineering News (1968) 46,3, p. 70, a particular reactant and product
are depicted as shown in F and G (see figure 12).
What are the IUPAC names ofF and G?
Answers to problems 23 to 27 are in 5.5.

Part two
Optional worl( and answers
to review problems

99
Chapter 3
Optional exercises
3.1 Additional exercises for Section A
You will require ball-and-stick or similar types of molecular models.
Ask for instructions and further help from your teacher if you have not
used such models before. You may be able to attempt the exercises
without using models by referring to figure 13.Answers are given
opposite or below the questions.
b
c
Figure 13
(a) Methane, CH 4 • (b) Chloromethane, CH 3 Cl. (c) Dichloromethane, CH 2 CI 2 •

100 Optional exercises
1
a Construct a model of methane, CH 4 . Are the hydrogen atoms in
methane arranged symmetrically round the central carbon atom?
b Suppose you removed one hydrogen atom from the model of methane,
would you obtain a different result depending on which hydrogen atom
you selected? (Give reasons for your answer.)
c Remove a hydrogen atom from the model of methane and replace it by
a chlorine atom. You now have a model of chloromethane, structural
H
I
formula H -C-Cl. Does this structural formula give a correct
I
H
picture of the arrangement of atoms in space?
d Examine your model of chloromethane, CH 3 Cl. Are the three hydrogen
atoms geometrically equivalent?
e Remove a hydrogen atom from the model of chloromethane, and
replace it with a second chlorine atom. How many models of compounds
of molecular formula CH 2 Cl 2 can you construct?
f Is the following statement correct? H -
CI
CI
I
I
C- Hand CI- C-
I
I
CI
H
H are the
structural formulae of two different compounds. (Give reasons.)
2 The molecular formula of ethane is C 2 H 6 ; its structural formula is
H H
a
I
I
H - C- C- H (see also figure 2 in AI, Chapter 1).
I I
H H
Construct a model of ethane. Replace one of the hydrogen atoms by a
chlorine atom. Is it possible to construct more than one model
corresponding to the molecular f.ormula C 2 HsCI?
H CI H H
I I I I
b Do the structural formulae H-C-C-H and H-C-C-CI
I I I I
H H H H
represent the same compound or two different compounds?

Optional exercises
101
c Remove one hydrogen atom from your model of C 2 HsCI, chloroethane.
Is it possible to do this in more than one way? (Give reasons.)
d The molecular formula C 2 H 4 Cl 2 corresponds to one/two/three different
compounds. Choose the correct term, and then construct one or more
models to help you check your answer.
Answers to 3.1
1
a The arrangement is symmetrical.
b All the hydrogen atoms are geometrically equivalent, so whichever is
removed, the result is the same.
c The arrangement of atoms in space is not indicated directly by the
structural formula.
d The three hydrogen atoms are geometrically equivalent.
e There is only one such compound (CH 2 CI 2 ).
f The statement is not correct. Both structural formulae represent the
same compound (see CH 2 Cl 2 in figure 13).
2
a
b
c
C 2 HsCI corresponds to only one compound. Replacing anyone of the
hydrogen atoms in ethane leads to the same result.
The two formulae represent the same compound, C 2 HsCI; see 2a above.
There are two different ways of removing one hydrogen atom from
C 2
H s Cl.
i. Removing one of the two hydrogen atoms on the carbon which is
bonded to chlorine.
ii. Removing one of the thr~e hydrogen atoms on the other carbon
atom.
d The molecular formula C 2 H 4 Cl 2 corresponds to two different
compounds; see 2c above.

102 Optional exercises
e How many different compounds are represented by the structural
formulae A to D? Construct models if you are doubtful about the
correct answer.
CI
I
H-C-C-H
I
H
CI
I
A
CI-C-C-H
I
H
D
CI
I
I
H
H
I
I
H
CI
I
H-C-C-H
I
CI
B
H
I
I
H
H H
I I
CI-C-C-CI
I I
H H
c
Note
You may find it interesting to observe the changes in relative positions
of atoms in ethane and substituted ethanes brought about by rotation
about the carbon-carbon bond. This may also help you with 2e above.
3.2 Additional exercises for Section B
Note
U sing models may help you with some of the questions.
Write your answers down (on a separate piece of paper) so that you can
check them accurately.
Instructions
Insert the correct term in the 'blanks', for example hydrogen in la below.
Choose the correct term where alternatives are given.
Answers are given opposite or below the questions.
1
a Hydrocarbons contain carbon and only. Alkanes, such as ethane
and propane, are a series of hydrocarbons in which all the carbon atoms
are linked to each other by single/double/triple bonds. If the systematic
IUPAC name of a hydrocarbon ends in -ane, we can assume that all
carbon atoms are linked by bonds.
b Methane contains one/two/three carbon atoms. Theftrst part of the
name of an alkane shows the number of carbon/hydrogen atoms present
in one molecule. Propane contains carbon atoms. C S H 12 is the
molecular formula of octane/pentane/neither of these compounds.
c The molecular/structural formula of hexane is C 6 H 14'

Optional exercises
103
Answer
e A to D represent two different compounds, molecular formula C 2 H 4 Cl 2 ;
see below for details.
Structural formula
Contracted structural
formula
CI CI H H
I I I I
H-C-C-H orCI-C-C-CI CI-CH 2 -CH 2 -CI
I I I I
H H H H
A
c
CI H CI H CI
I I I I I
H-C-C-HorCI-C-C-H CI-CH-CH 3
I I I I
CI H H H
B
D
Answers to 3.2
1
a hydrogen, single, single.
b one, carbon, three, pentane.
c molecular.

104 Optional exercises
d In alkanes such as ethane, H -
H H
I I
C - C-
I I
H H
H, each carbon atom is
linked to other atoms (carbon and hydrogen) by two/three/four single
bonds.
e C-C-C-C represents the carbon chain in octane/heptane/butane.
-
I I I I
C- C- C- C-
I I I I
indicates that each carbon atom is linked
to other atoms (carbon and hydrogen) by single bonds. To
complete the structural formula of this compound, the correct number
of hydrogen atoms must be inserted, that is, eight/ten/twelve hydrogen
atoms.
f The molecular/structural formula of pentane is
H H H H H
I I I I I
H - C- C- C- C- C-
I I I I I
·H H H H H
H. A simplified (condensed) structural
formula for pentane is .
g The expanded structural formula H -
H H H
I I I
C- C- C-
I I I
H H H
H can be
contracted to CH 3 -CH 2 -CH 3 , and further to CH 3 CH 2 CH 3 • Which
of the following represent (i) hexane, C 6 H 14 , (ii) octane, C S H 18 ,
(iii) neither of these compounds?
CH 3 (CH 2 )6CH3, CH 3 (CH 2 )4CH3, CH 3 (CH 2 )gCH 3 ,
CH 3 CH 3
I
I
CH 2 -CH 2 -CH 2 -CH 2 •
2
a The IUP AC names of CH 3 CI, CH 2 Br 2 and CF 4 are , ,
and These compounds are alkanes/halogenoalkanes/neither.
b The formulae BrCH 2 CH 3 and CH 3 CH 2 Br do/do not represent the same
compound.
c The compound CH 3 CH 2 I is named iodethane/l-iodethane/
2-iodethane.
d The IUPAC name ofCH 3 CHF 2 is difluorocthane/l-difluoroethane/
2-difluoroethane/l,1-difluoroethane/2,2-difluoroethane.

Optional exercises
105
e The expanded structural formula of CH 2 FCH 2 F is .
f The compound CH2FCH2F is named difluoroethane/l,2-fluoroethane/
1,2-difluoroethane.
g Which of the following is not a correct condensed formula for
1,2-difluoroethane? (i) CH2FCH 2 F, (ii) FCH2CH2F,
(iii) CH2- F-CH2- F, (iv) F-CH2-CH2- Fo
3
a The IUPAC name ofCHBr2CHBr2 is tetrabromoethane/
1,I-dibromo-2,2-dibromoethane/l, 1,2,2-tetrabromoethane/none of
these.
b The IUPAC name ofCH2BrCH2Cl is l-chloro-2-bromoethane/
1-bromo- 2-chloroethane/l ,2-bromochloroethane/
1,2-chlorobromoethane/none of these.
Answers
d four.
e butane, four, ten.
f structural, CH3CH2CH2CH2CH3; alternatively
CH3-CH2-CH2-CH2-CH3 or CH3(CH2hCH3.
CH3
CH3
I
I
g i. hexane: CH3(CH2)4CH3 and CH2-CH 2 -CH2-CH2
ii. octane: CH3(CH2)6CH3'
iii. neither of these compounds: CH3(CH2)gCH3 (formula of decane).
2
a chloromethane, dibromomethane, tetrafluoromethane, halogenoalkanes.
b do.
c iodoethane.
d
1,I-difluoroethane.
F F H H H F
I I I I I I
e H-C-C-H (alternatively F-C-C-F or F-C-C-H).
I I I I I I
H H H H H H
f 1,2-difluoroethane.
g CH2- F-CH 2 - F, (iii) is not correct (see 4.1c).
3
a 1,1,2,2-tetrabromoethane (IUPAC name ofCHBr2CHBr2).
b I-bromo-2-chloroethane (IUPAC nameofCH2BrCH 2 CI; note
alphabetic order of substituents in systematic name).

106 Optional exercises
4
11 21 31 41
a - C- C- C- C- represents the carbon chain in
I I I I
b
1,1,1,3-tetrafluorobutane. Inserting the four fluorine atoms in the
formula, we obtain Completing the formula by inserting
hydrogen atoms, we obtain .
The condensed structural formula of 1,1,1,3-tetrafluorobutane
is .
c The structural formula of I-bromo-2,2-difluoroethane is (Give
expanded or condensed structural formula.)
d The formula of pentane is CH 3 (CH 2 hCH 3 • Write down the structural
formulae (expanded or condensed) of (i) 2,3-dichloropentane,
(ii) 3-bromo- 2-chloropen tane, (iii) 3,3-dibromo- 2,2-dichloropen tane.
5
a The IUPAC name ofCH 3 CH 2 CH 2 CI is chloropropanej
3-chloropropanej l-chloropropanej3chloropropanej 1chloropropane.
b The IUPAC name ofCH 3 CH 2 CHCl 2 is 3-3-dichloropropanej
3,3-dichloropropanejl-l-dichloropropanejl, I-dichloropropane.
c The compound CH 3 CHCH 2 CH 2 CH 3 is named .
I
CI
d The formulae CH3CHCH2CH3, CH 3 CH2CHCH 3 , and CH 3 CH2CHCI
I I I
CI CI CH 3
dojdo not represent the same compound. Give the IUPAC name(s) of
the corresponding compound(s);
e Give the IUPAC names of CH 3 CHCI and CH 3 CHCl.
I
CH 3
I
CH 2 CI

Optional exercises
107
Answers
4
F F F H F H
I I I I I I I I
a F-C-C-C-C- F-C-C-C-C-H.
I I I I' I I I I
F F H H H
b CF 3 -CH 2 -CHF-CH 3 or CF 3 CH 2 CHFCH 3 •
c
d
Examplesof correct ways of writing the structural formula:
H F H F
I I I I
Br-C-C-F, Br-C-C-H, CH 2 Br-CHF 2 , BrCH 2 CHF 2 •
I I I I
H H H F
Examplesof correct ways of writing the structural formulae:
H H H H H
I I I I I
i. H-C-C-C-C-C-H or CH 3 CHCICHCICH 2 CH 3
I I I I I
H CI CI H H
H CI H H H
I I I I I
ii. H-C-C-C-C-C-H or CH 3 CHCICHBrCH 2 CH 3
I I I I I
H H Br H H
H CI Br H H
I I I I I
iii. H-C-C-C-C-:"'C-H or CH CCI CBr CH CH .
I I I I I 32223
H CI Br H H
5
a
b
c
d
e
l-chloropropane.
1,I-dichloropropane.
2-chloropentane.
do, 2-chlorobutane (the longest continuous carbon chain is generally,
but not always,written horizontally).
2..chloropropane, 1,2-dichloropropane (in both casesthe carbon chain
contains three carbon atoms, the formulae are more usually written as
CH 3 CHCICH 3 and CH 3 CHCICH 2 CI).

108
Optional exercises
3.3
Additional exercises for Section C
Note
Using models may help you with some of the questions. Write your
answers down (on a separate piece of paper) so that you can check them
accurately.
';.3
Instructions
Insert the correct term in the blanks; choose the correct term where
alternatives are given.
Answers are given opposite or below the questions.
1
a The reactions of an organic compound frequently involve the functional
group. The - OH (hydroxyl) group is the group of alcohols such
as methanol, CH 3 0H. The hydroxyl group is indicated in a systematic
name by the ending The IUPAC name ofCH 3 CH 2 0H is
ethan-I-ol/ethanol/neither.
b The IUPAC name ofCH 3 CH 2 CH 2 0H is propan-I-ol/propan-3-01/
neither.
c Propan-2-01, structural formula , is an isomer of propan-I-ol.
These compounds have the same molecular formula/structural formula/
molecular and structural formulae.
d The IUPAC name ofHOCH 2 CH 2 0H is diethanol/ethanediol/neither.
e The structural formula of butane-l ,2-diol is .
2
a Alkenes are a series of compounds which contain the functional
group. This is indicated in IUPAC names by the ending .
b The suffix -diene shows the presence of one/two group(s), -dial
the presence of one/two group(s).
"" /
c The suffix -yne indicates that a C=C / -C-C- group is
present. / ""
d The presence of carbon atoms arranged in a ring is shown by the
prefix CH 2 - CH 2 is the formula of .
I
I
CH 2 -CHCI
3
a The formulae CH 3 CH=CH 2 and CH 2 =CHCH 3 do/do not represent
the same compound. Give the IUPAC name(s) of the corresponding
compound(s).

Optional exercises
109
b CH 3 CH==CHz is named propene. In compounds containing longer
""- /
chains of carbon atoms, the position of the C==C groups must be
/ ""-
indicated by numbering. CH 3 CH 2 CH==CHCH 3 is named pent-2,3-ene/
pent-2-ene/neither. A single number is/is not sufficient to indicate the
""- /
position of one C== C group.
/ ""-
C CH 3 CH 2 CH==CH 2 is named butene/but-l-ene/but-2-ene/but-3-ene.
d The formula ofpenta-2,3-diene is CH 3 CH 2 CH=CHCH 3 /
CH 3 CH = C= CHCH 3 /neither.
Answers to 3.3
1
a functional, -01, ethanol (see 4.4 if your answer was ethan-I-a!).
b propan-I-ol (see e2, Section C, if your answer was propan-3-ol).
c CH 3 CHCH 3 (or CH 3 CH(OH)CH 3 ), molecular formula.
I
OH
d neither (ethane-l,2-diol is correct, see C3).
e CH 3 CH 2 CHCH 2 0H, or CH 3 CH 2 CH(OH)CH 2 0H.
I
OH
2
""- /
a C==C,
/ ""-
-ene.
""- /
b two, C==C , two, -OH (hydroxyl).
/ '"
c -C-C-.
d cyclo-, chlorocyclobutane (see C17 and 4.4 if your answer was
l-chlorocyc1o bu tane).
3
a do, propene (read 4.4 if your answer was prop-l-ene).
b pent-2-ene, is (see C8 if your answer was not correct).
c but-l-ene.
5 4 321
d CH 3 CH=C=CHCH 3 (see CII).

110
Optional exercises
,,3
4
a CH3CHCH2CH3 is named , CH3CHCH2CH3 is
I
CI
CH3
named .
b The compound CH3CHCH3 is named butane/butene/neither.
I
CH 3
C CH 3 -CH-CH20H is named '
I
CH 3
d The formula of l-chloro-2-methylpropane is ,
I
5
a
The longest unbranched (continuous) carbon chain in 2-methylpentane
contains five/six/seven carbon atoms.
b Complete the formula of3-methylhexane: C-C-C-C-C-C,
I
C
c The formula of 3-methylheptane can be written as
CH3CH2CHCH2CH2CH2CH3/CH3CHCH2CH2CH2CH3/both/
neither. I I
CH 3
CH2CH3
6
a The formula of 2,2,3-trimethylpentane is ,
b
CH 3
I
The systematic name for the compound CH3CH2-C-CH3
I
CH 3
is:
ethyltrimethylmethane/l-trimethylpropane/l,
I, l-trimethylpropane/
2,2-methylbutane/2,2-dimethy lbutane/3 ,3-dimethy lbutane.
CH 3
I
c The systematic name for the compound CH 3 - C-CH 3 is ,
'I
CH 3
7
a CH2 - CH2 is named propanol/cyclopropanol/neither. Give the
'\/
CHOH
formulae of cyclopropane and cyclopropene,

Optional exercises
111
b Isomers are defined as compounds which have the same molecular
formula/structural formula/functional group.
e CH 2 -CH 2 (name ) and CH 3 CH=CHCH 3 (name )
I
CH 2 -CH 2
have the same
I
formula and are/are not isomers.
Answers
4
a 2-chlorobutane, 2-methylbutane.
b neither (2-methylpropane is correct, see CI9).
e 2-methylpropan-I-ol (see C25).
d CH 3 -CH-CH 2 Cl.
I
CH 3
5
a five.
b CH 3 -CH 2 -CH 2 -CH -CH 2 -CH 3 (you may have given a fully
I
CH 3
expanded formula).
e
both (in the second formula the longest continuous chain is not written
horizontally, see C20).
6
CH 3
I
a CH 3 -C-CH-CH 2 -CH 3 (see C24).
b
e
I I
CH 3 CH 3
2,2-dimethylbutane (the longest carbon chain contains four carbon
atoms, see C2l).
2,2-dimethylpropane (see C2I).
7
a cyclopropanol, CH 2 -CH 2 , CH===CH (see CI6 and CI7).
b
e
'" / '" /
CH 2 CH 2
molecular formula.
cyclobutane, but-2-ene, molecular, are (see CIO).

112 Optional exercises
8
a
b
The total number of carbon atoms in a molecule of
3-ethyl-4-methylheptane is seven/eight/nine/ten.
What are the functional groups in each of the following?
3-methyloct-l-ene, 3-chlorodecane, 3,3-dimethylhexane-l,2-diol.
9 Each of the following names contains one or more mistakes. Give
correct IUP AC names.
a. CH 3 CH=CH 2 : prop-l-ene.
b. CH 3 CH 2 CH=CH 2 : butan-l-ene.
c. CH 3 CH=CHCH 3 : but-l,2-ene.
d. CH 2 =CHCH=CH 2 : buta-l,3-ene.
e. CH 3 CHCH 3 : prop-2-0l.
I
OH
f CH 3 CH 2 CH 2 0H: propyl-l-ol.
g. CH 3 CBr 2 CHBr 2 : 1,2-tetrabromopropane.
3.4 Additional exercises for Section D
Note
W~iting your answers down on a separate piece of paper will enable you
to check them accurately. Answers are given opposite the questions.
1
a The functional group in hex-2-yne is the group.
b Acetylene, formula , contains a "- C=C / -C=C- group/
neither. / "
c The compound CH 3 C-CH is named .
;0 represents the compound , molecular formula .
b
In 1865, Kekule suggested that the formula of benzene was A/B.
HC
I
HC
CH
~ "-
~ /
CH
A
CH
II
CH
HC
I
HC
CH
/ "-
'" CH/
B
CH
I
CH

Optional exercises
113
Answers
8
a
ten.
"" /
b C=C, -Cl, -OR (two groups).
/ ""
9 a. propene
b. but-I-ene
c. but-2-ene
d. buta-I,3-diene
e. propan-2-o1
f propan-I-ol
g. 1,1,2,2-tetrabromopropane
(seeC8 and CII for names of alkenes, C2 for alcohols, and Bl3 for
halogenoalkanes).
Answers to 3.4
1
a -C=C-.
b HC=CH(C 2 H 2 ), -C-C-.
c propyne (methylacetylene) (seeDI).
2
a benzene, C 6 H 6 •
b A.

114 Optional exercises
e
The structural formula of toluene (methylbenzene) is C/D.
CH 3
I
CH
/ "- HCQCH
I
HC
"- CH/
C
I
CH
CH 3
I
C
/ .'"
HCQCH
I
HC
"- CH/
D
I
CH
d The name of C 6 HsCH 2 CH3 is .
e The formula of styrene (phenylethylene) is .
3
a The formula of chlorobenzene is C 6 HsCI/C 6 H 6 CI/neither.
b C 6 Hs - is the phenol/phenyl group.
e The formula of nitrobenzene is E/F.
E
F
d Ethanol (formula ) and phenol (formula ) each contain
a group.
4
a
The formula of ethanal is CH3CH20H/CH3CHO/CH3CH2CHO.
This compound is generally called , and its expanded structural
formula is .
o
b H -
~
C is an aldehyde/a carboxylic acid/neither.
"- H
e The formula of acetic acid is An alternative name for this
compound is methanoic/ethanoic acid.

Optional exercises
115
Answers
C D (see D2).
d ethylbenzene (phenylethane) (see D4).
CH=CHz
e O(C6H5CH=CH2) (see DS).
3
a C 6 HsCI (see D2).
b phenyl (see D4).
C F (see D2).
OR
d CH 3 CH20H,O(C6H50H), -OH (hydroxyl) (see DS).
4
H 0
I ~
a CH 3 CHO, acetaldehyde, H - C- C (see DII).
I ~
H H
b
aldehyde.
o
~
C CH 3 -C (CH 3 C0 2 R), ethanoic acid (see Dll).
""
OH

116 Optional exercises
d The formula of acetyl chloride is CH 3 -
~
C . The functional group
in this compound is
"Cl
e CCl 3 C0 2 H is the formula of trichloroacetaldehyde/trichloroethanol/
trichloroacetic acid/none of the compounds.
f The expanded structural formula of acetic acid is .
o
5
a
b
" C=C /
/ .'"
Which series of compounds contain the following functional groups?
-C C- -CHO
What are the functional groups in each of the following?
hexanoic acid, cyclohepta-I,3 ,5-triene, propane-l ,2,3-triol.
6
a The compound CH 3 -C=CHCH 3 is named 2-methylbut-2-ene/
I
CH 3
2-methyIbut-2,3-ene/3-methyl but-3-ene/3-methyl but-2,3-ene/
3-methylbut-2-ene/2-methy lbut -3-ene.
b The formula of 2,2-dimethylpentan-I-ol is .
CH 3
I
c The compound CH 3 CH 2 COH is named l,l-dimethylpropan-I-ol/
I
CH 3
trimethylethanol/2-methylbutan-2-ol/none of these.
d The formula ofpentanoyl chloride is CH 3 (CH 2 hCOCI/
CH 3 (CH 2 )4 COCI/neither.

Optional exercises
117
:; .4
Answers
o
/l
d -c (-CaCI, acid chloride) (see D7).
~
CI
e trichloroacetic acid (see D 13).
H 0
I /l
f H - C-C (see D7 and DI1).
I ~
H OR
5
a carboxylic acids, alkenes, alkynes, aldehydes.
o
/l "" /
b -C0 2 H (-C, ' carboxyl), C=C (3 groups),
'" / ""
OR
-OH
(3 groups).
6
a 2-methylbut-2-ene (see C8 and C2l).
CR"l
I -
b CH 3 CH 2 CH 2 CCH 2 0H (see C25).
I
CR 3
c 2-methylbutan-2-o1 (see C25).
d CH 3 (CH 2 hCOCI (see D7).

119
Chapter 4
Review and extension information
4.1 Structural formulae
4.1 a Interpretation of structural formulae
One of the simplest ways of representing a molecule is by means of a
structural formula. This shows which atoms are bonded to each other
and the types of bonds present (see A 7). It is important to remember that
structural formulae are only conventional symbols, and that the precise
way in which they are interpreted has evolved and changed over the
last hundred years in the light of new experimental data and theoretical
ideas about the structure of atoms and molecules.
Formulae such as those below indicate how the relevant atoms are
linked (whether by single, double, or triple bonds), but provide no direct
information about the forces which bind the atoms, the relative position
of the atoms in space, the actual distance between atomic nuclei
(internuclear distance or bond length), and so on. The figure references
given below are to illustrations of models of the relevant compounds.
H H
I I
H-C-C-H
I I
H H
ethane
H H H H H
I I I I I
H-C-C-C-C-C-H
I I I I I
H H H H H
pentane
see figure 2, Al
see figure 3b, A2
H H
" C=C /
H
/ ."
ethene
see figure 6, C7
H
see figure 7, C28

120
Review and extension information
A chemist who is familiar with modern ideas of molecular structure can
interpret these formulae in terms of features such as bond character,
bonds lengths, and molecular shape. He is aware for example that
carbon-carbon single bond lengths are virtually identical in most
molecules. Carbon-carbon double bond lengths are shorter than the
single bond lengths, but again essentially the same in most molecules.
Unusual bond length values generally indicate bonds which are not
ordinary single or multiple bonds. In such cases an ordinary structural
formula does not represent adequately the bond arrangement in the
molecule (see formula of benzene, 4.1b). Some of the bonds present in
such molecules are different from simple single, double, or triple bonds.
.1 b
This is one limitation of simple structural formulae. In addition, as
mentioned earlier, they are not intended to represent directly the
geometry of the molecule (see A7). The carbon chain in pentane is not
'straight'; cyclohexane is not a 'flat' molecule (see the illustration of
models in figure 3 in A2 and figure 7 in CI8).
Nevertheless, structural formulae are extremely useful to organic
chemists, particularly since they show thefunctional group present (see
C1). This group confers a characteristic reactivity on a compound.
4.1 b Formula of benzene
Benzene, C 6 H 6 , is an example of an arene or aromatic compound. Kekule
first suggested a cyclic structural formula for benzene, making use of his
earlier theory about the 'combining power' (valency) of carbon being
equal to four in all compounds (see D2). This formula, and a modified
one suggested by Kekule in 1872, failed to account for a number of
experimental facts. Cyclohexene and other alkenes, for instance,
decolorize aqueous solutions of potassium permanganate at room
temperature, but benzene does not.
H
I
H C H
.'" ~ "" /
C
I
C
C
II
C
/ ~ / .'"
H C H
I
H
formula of benzene
(Kekule, 1865)
cyclohexene

Review and extension information
121
The six carbon atoms in benzene have now been shown to be
geometrically equivalent (see models of benzene, figure 8, D2). The six
carbon-carbon bond lengths are identical, and intermediate between
single and double bond lengths (see 4.1a). Other evidence also strongly
indicates that the benzene ring is a planar symmetrical system and does
not contain alternate single and double bonds.
The structure of benzene and other aromatic compounds has been the
subject of intense research by theoretical and experimental chemists
right up to the present day.
One area of special interest has been the investigation of different types
of cyclic systems aimed at identifying the kind of structural features
which are responsible for aromatic character (see answer to problem 26,
in 5.5). You may already be aware of how the special characteristics of
benzene and related compounds have been explained in terms of
'delocalized' electrons. (Consult your teacher or use a reference book for
further details.)
Benzene is not a simple cyclic triene. The original Kekule formula (see
above) is inadequate for representing its structure. Formulae which
highlight the special aromatic character of benzene, and in particular, the
equivalence of the six carbon-carbon bonds are generally the most
useful.
A and B (see below) are used in this text; slightly different representations,
C and D, are given in some books. Substituted benzene compounds are
represented in the same way, for instance 1,4-dibromobenzene, E. Some
aromatic compounds have ring systems different from benzene; an
example is pyridine, F.
Benzene 1,4-Dibromobenzene Pyridine
C 6 H 6 C 6 H 4 Brz CsHsN
Br
H I H
C
0 0 0
C
c
H909H HCOCH
I I H909H
HC" /,CH ~~.... ~.. .........•.... '
HC" /,CH HC" /,CH
C N
H
rBr
A B C D E F

122 Review and extension information
4.1c Condensed and expanded structural formulae
Structural formulae are a means of conveying the structure of a
compound in a concise manner, and must be written in ways which
permit the clearest possible communication of important structural
features. This is sometimes best achieved by writing out a formula fully
showing all the bonds (expanded formula). In other cases condensed
formulae can be used (see A7).
Condensed formulae can be written in different ways, for instance for
ethanol, CH 3 CH 2 0H or C 2 HsOH (see also Note 2 in 4.6a).
CH 3 CH 2 0H might be used with advantage for reaction 1 below, in
which the methyl group, CH 3 -, is unchanged. The ethyl group,
C 2 H s -, is unaffected in reaction 2, and the formula C 2 HsOH is
.1e perhaps most appropriate.
1 CH 3
CH 2
0H oxidation) CH 3
CHO
acetaldehyde
(ethanal)
2 C H 2 s OH HBr) C H 2 s Br
bromo ethane
Further abbreviations, such as Me for methyl, Et for ethyl (see 4.6b) are
used. 2,2-dimethylpropane can be represented as A or B (see figure 4
in A4).
CH 3
I
CH -C-CH
3 I 3
CH 3
Me
I
Me-C-Me
I
Me
A
B

Review and extension information
123
It is most important to write condensed formulae correctly. Examples
are given in B22, DI5, 3.2, and 3.4. Others are given below.
Compound Correct condensed formulae Incorrect formulae
1,2-difluoroethane FCH2CH2F, CHzFCH 2 F CFH2CFH2
ethane-I,2-diol CHz-CH 2 , HOCH2CHzOH OHCHzCHzOH
I I
OH OH
CH3
I
2,2-dimethylbutane CH3CCH2CH3, CH3C(CH3)2CH2CH3 CH3CCH3CHzCH3
I
I
CH3 CH 3
prop anal CH3CHzCHO, CzHsCHO CH3CH2COH
propanoic acid CH 3 CHzC02H, C2HsC02H CH 3 CH 2 CH02, CO Z HC2Hs
\.j.
.le
Note
1. Study the above table carefully. Formulae are conventional
representations of molecules, designed to convey information in an
unambiguous way. Incorrectly written formulae may suggest the wrong
kind of information.
2. Hydrogen is usually written after the atom to which it is bonded.
H H
I I
H-C-C-H CH 2 FCH 2 F (not CFH 2 CFH 2 )
I I
F F
1,2-difluoroethane

124
Review and extension information
3. A formula such as CH3CH2CH2CH2CH3 represents
-C-C-C-C-C-,
an unbranched chain of five carbon atoms.
It would be misleading to write CH3CHCH3CH2CH3 as a contraction
of CH3CHCH2CH3.
I
CH 3
Brackets
are used, for instance
.le
CH 3 CHCH 2 CH3 is represented as CH 3 CH(CH 3 )CH 2 CH 3
I
CH 3
CH 3
I
CH3CCH2CH3 is contracted to CH3C(CH3hCH2CH3 .
I
CH 3
4. A molecularformula can be used as the simplest possible condensed
structural formula where it corresponds to only one compound, for
example C 2 H 6 . A molecular formula must not be used as a structural
formula in other cases, for instance C 2 H 6 0 (see structural isomers, 4.2).
Molecular Expanded structural
formula formula Condensed formula
H
I
H
I
C 2 H 6
H-C-C-H CH 3 CH 3 , C 2 H 6
I
I
H H
ethane
H
I
H
I
C 2 H 6 O H-C-C-O-H CH 3 CH 2 0H, C 2 H s OH
I
I
H H
ethanol
H
I
C 2 H 6 O H-C-O-C-H CH 3 OCH 3
I
H
dimethyl
H
I
I
H
ether
(methoxymethane)

Review and extension information
125
4.2 Structural isomers
Structural isomers are compounds with the same molecular formulae
but different structural formulae. A number of examples have already
been given, see for instance C8, CIO, CI9, 2.2 (problems 9 and 10),3.1,
and 3.3. Models of three isomers of molecular formula C S H 12 are shown
in figures 3 and 4 in A2 and A4.
In some cases, isomers contain the same functional group (see Cl) and
therefore belong to the same series of compound; in other cases different
functional groups are present. Examples are given below.
Structural isomers containing the same functional group
Series and Molecular
functional group formula Isomers
.2
~lkenes C 4 H s A CH 3 CH 2 CH=CH 2 but-I-ene
B
'" / CH 3 CH=CHCH 3 but-2-ene
C=C
/ '"
CH 3
I
C CH 3 C=CH 2 2-methylpropene
alcohols C 4 H 1O O D CH 3 CH 2 CH 2 CH 2 OH butan-I-ol
-OH E CH 3 CH 2 CHCH 3 butan-2-o1
I
OH
CH 3
I
F CH 3
-CH -CH 2 OH 2-methylpropan-l-ol
CH 3
I
G CH -C-CH 2-methylpropan-2-o1
3 I 3
OH
Note
1. Some of the above isomers have the same 'carbon skeleton', but the
functional groups are attached in different positions, for instance D and
E. Others have different carbon skeletons, for instance D and F.
2. The compounds in the above table do not necessarily represent all
isomers with molecular formula C 4 Hs and C 4 HsO, but only those with
"'. /
functional groups C=C and -OH respectively. Cyclobutane for
/ .'"
instance also has the molecular formula C 4 Hs (see CI6).

126
Review and extension information
Structural isomers containing differentfunctional groups
Molecular
Series and functional group formula Isomers
alcohols -OH C 2 H 6 O CH 3 CH 2 OH ethanol
ethers -0- CH 3 OCH 3 dimethyl ether
(methoxymethane)
aldehydes -CHO C 3 H 6 O CH 3 CH 2 CHO propanal
.2
ketones -C- CH 3 CCH 3 acetone (propanone)
II
II
° °
carboxylic acids -C0 2 H C 3 H 6 0 2 CH 3 CH 2 C0 2 H propanoic acid
esters -C0 2 R CH 3 C0 2 CH 3 methyl acetate
(methyl ethanoate)
Note
As in the previous table the above do not necessarily represent all
possible isomers of tbe relevant molecular formulae. The reaction
between propene and certain oxidizing agents, for instance, produces a
compound of molecular formula C 3 H 6 0, structural formula
CH 3 CH--CHz.
This compound, 1,2-epoxypropane, is an isomer of
'" /
a
propanal and acetone (see above), and is of considerable commercial
importance.
Simple molecular formulae generally correspond to only a few
structural isomers. CzH 4 Clz is the molecular formula of
1,1-dichloroethane and 1,2-dichloroethane (see 3.1, 2). Some molecular
formulae represent a single compound, for instance CzHsCI,
chloroethane (see 3.1, 1).
One can frequently deduce the number of possible isomers by writing
down structural formulae in which each carbon atom is linked to other
atoms by four covalent bonds, each hydrogen by one covalent bond,
each oxygen by two, and so on. Care is needed in interpreting these, and
the use of molecular models will avoid the possibility of incorrectly

Review and extension information
127
H
Cl
r
I
identifying H - C-CI and H - C- H as two different compounds
I
I
Cl
Cl
(see 3.1). It is also important to consider the possibility of cyclic isomers
and to note that some isomers may not be stable under ordinary
conditions. C 2 H 4 0 for instance, is the molecular formula of three
compounds (systematic names in brackets).
0
-f'
CH-c CHz=CHOH CHz-CHz
3 .'"
"
H 0/
acetaldehyde vinyl alcohol ethylene oxide
(ethanal) (ethenol) (epoxyethane)
Vinyl alcohol is not normally stable (it is converted to acetaldehyde).
Acetaldehyde and ethylene oxide are stable and manufactured in large
quantities.
The synthesis of isomers of unusual structure has received considerable
attention recently. An example is cubane, molecular formula CsHs; see
L in figure 14. This is an isomer of a number of open-chain carbon
compounds, and also of cyc100cta-l,3,5,7-tetraene (see M below and
problem 26 in 2.5) and styrene (see N).
/~H /CH
CH-;---CH
/CH········ ./CH
CH---CH
L
CH=CH
/ '"
CH
II
CH
'" /
CH=CH
M
CH
II
CH
CH=CHz
I
C
/ '",
HCOCH
I
HC
.'" /
CH
N
I
CH
Figure 14
Three isomers, molecular formula CsH s .
Note
See 4.3 and 4.4 for some additional points relating to isomers.

t •••••
128 Review and extension information
4.3 Primary, secondary, and tertiary carbon atoms
A primary carbon atom is attached to one other carbon atom (the
carbon atom in CH 4 , and in CH 3 0H is a 'special' case of this). A
secondary carbon atom is attached to two other carbon atoms; a tertiary
carbon to three. The term 'quaternary' for a carbon atom attached to
four carbon atoms is rarely used.
Compound ethane propane 2-methylpropane
--
:primary
.3
Type of
carbon
atom
.....•.. '
I CH 3
-f-CH 3 i
:primaryjprimary:
...•
J pr~::ry isec~:d2ary Ipr~~:ry I
: CH 3
,.. I .... ·..·: :
CH3--T-CH~CH3 ~
primary: tertiary :primary\
This classification is useful in a number of ways. For example:
1 Differences in reactivity
a. Alkanes. Hydrogen attached to a tertiary carbon is for instance
replaced by chlorine more rapidly than hydrogen on a primary carbon.
b. Halogenoalkanes and alcohols. These compounds are classified as
primary, secondary, and tertiary, according to the type of carbon atom
to which the functional group is attached. (Unfortunately in another
series of compounds, amines, the terms primary, secondary, and so on,
are used in a different way.)
ethanol 2-chloropropane 2-methylpropan-2-ol
CH 3 -CHz-OH CH3-CH-CH3 CH3
a primary alcohol I I
Cl CH
(-OH group
3 -C-CH 3
I
bonded to a
a secondary
OH
primary carbon
halogenoalkane a tertiary alcohol
atom)

Review and extension information
129
The ease with which primary, secondary, and tertiary alcohols (or
halogenoalkanes) react differs in many cases. An example is the
dehydration of alcohols to form alkenes. Ethanol, a primary alcohol,
requires a higher temperature and more concentrated acid than
2-methylbutan-2-ol, a tertiary alcohol.
CH 3
I 46 per cent H 2 S0 4
CH 3 CH 2 -C-CH 3 )
I 87°C
OH
tertiary alcohol
CH 3
I
CH 3 CH=C-CH 3
2-methylbut-2-ene
Note
You might wish to speculate on the likely product obtained by the
CH 3
dehydration ofCH 3 -C-CH 2 CH 2 CH 2 -OH
conditions.
6H
I
under mild
Another way in which this classification of carbon atoms can be useful
is discussed on the next page.

130 Review and extension information
2 Number of isomers
Classifying carbon atoms into primary, secondary, and tertiary
sometimes helps to decide on the number of isomeric compounds which
can exist. Ethane contains two equivalent primary carbon atoms, so
replacement of anyone hydrogen gives the same compound.
2-Methylpropane contains three equivalent primary carbon atoms and
one tertiary, and so forms two different monochloro compounds on
substitution. (See the table at the top of page 128.)
CH 3 -CH 3
ethane
+ Cl 2 ~ CH 3 -CH 2 CI + HCI
chloroethane
primary halogenoalkane
/
CH 3
I
CH 3 -CH-CH 2 Cl
1-Chloro-2-methYIPropane
primary
halogenoalkane
+ HCI
+ HCI
2-chloro-2-methy Ipropane
tertiary halogenoalkane
4.4 Numbering of carbon atoms
The purpose of numbering carbon atoms in systematic names is to
provide precise information about the structure of a compound. This
numbering is omitted when a structural formula can be deduced without
the use of such numbers. The examples which follow illustrate this.
References are made to sections which contain further details of names
and formulae of the particular type of compound. (Molecular models,
if available, may prove especially helpful here.)

Review and extension information 131
CH 3 CHzCI
chloroethane
(B2-B4)
Only one such compound exists. The two carbon atoms in
ethane are equivalent, it does not matter which is bonded
to the chlorine atom, when CH 3 CHzCI is formed (3.1).
Chloroethane is therefore sufficient for deducing the
structure unambiguously. 'I-Chloroethane' provides
superfluous information.
CH 3 CHzOH
(C2)
CH 3 CH=CHz
propene
(C8)
Not ethan-l-01 (for details see chloroethane above).
Not prop-l-ene. Only one compound containing a chain of
three carbon atoms and one double bond can exist,
essentially
'"
I
/
C=C-C-.
I
CH-CHz
II
I
CH-CHz
cyclobutene
(CI6)
Not cyclobut-l-ene. Only one such compound is possible.
Cyclobutane is a symmetrical system, hence it does not
matter where a double bond 'forms' to give cyclobutene.
(Similarly cyclohexene, chlorocyclobutane, etc.)
CH 3 CHzCHzCHO
butanal
(D7)
Not butan-l-al. The -CHO group at the end of the chain
is by convention numbered I, even when a longer chain
exists in a different part of the molecule. This is understood
without writing 1 in the name.
CH 3 CHzCOCH 3
butanone
Not butan-l-one. Only one compound, containing an
unbranched chain of four carbon atoms, and a C=O
group situated between two other carbon atoms can exist,
essentially C-C-C-c.
II
o
Not l-chlorobenzene. The six carbon atoms in benzene are
equivalent (see 4.1 b).
6chlorobenzene
(D2)

132 Review and extension information
4.5 Saturated and unsaturated compounds
4.5a Types of reactions
Carbon atoms in alkanes and substituted alkanes are bonded to other
atoms by four single bonds (see examples below, and models of these
molecules in figure 3, A2, and figure 13, 3.1).
H H H H H
I I I I I
H-C-C-C-C-C-H
I I I I I
H H H H H
pentane
H
I
H-C-CI
I
H
chloromethane
H
I
H-C-H
f
Iff
H-C-C-C-C-H
I I I I
H H H H
2-methylbutane
Cyc1oalkanes, such as cyc10hexane (see figure 7, CI8), and alcohols such
as ethanol, also contain carbon atoms linked in this way. The four
valencies of carbon have been 'saturated' by single bonds; no further
groups can be attached to the carbon atoms. You may be aware of how
this 'saturation' is explained in terms of modern theories of chemical
bonds. (Ask your teacher or use a reference book for further details.)
Saturated compounds react by substitution of one group for another; no
further groups can be added.
CH 3 CH 3 + Cl 2 -+
ethane
CH 3 CH 2 CI
chI oro ethane
+ HCI
Unsaturated compounds contain multiple (double or triple) bonds and
react mainly in addition reactions. (You may wish to ask your teacher
or use a reference book for details about the nature of multiple bonds.)
CH 2 =CH 2 + Br 2 -+ CH 2 BrCH 2 Br
ethene
(ethylene)
1,2-dibromoethane
Saturated compounds can react by substitution only. Unsaturated
compounds generally undergo addition reactions, but may react by

Review and extension
information
133
substitution as well. Propene, for instance, yields mainly
3-chloropropene when treated with chlorine at high temperature. The
addition product, 1,2-dichloropropane, is more generally the main
product.
CI 2
500-600 DC
CH 3 CH-CH 2
I
CI CI
15per cent
1,2-dichloropropane
I
; ; .5a
Further examples of saturated and unsaturated compounds are given
below. (Benzene is generally classified as an unsaturated compound
which has special aromatic character; see 4.lb.)
Series and
Type of functional
compound group Example of reaction
saturated alcohols CH 3
CH 2
-OH + HBr sUbstitutio~ CH 3 CH 2 Br + H 2 O
-OH ethanol bromoethane
unsaturated alkynes CH=CH + 2Cl 2
addition )
CHCl 2 CHCI 2
-C=:C- acetylene l,I,2,2-tetrachloroethane
(ethyne)
0
~
addition )
unsaturated aldehydes CH -C + HCN CH3-?H-OH
0 3 '"
~ H CN
-C acetaldehyde acetaldehyde cyanhydrin
'"
(ethanal)
H
Note
Acetaldehyde is an unsaturated compound because the oxygen atom is
linked to the carbon atom by a double bond. The product obtained by
the addition reaction between acetaldehyde and hydrogen cyanide (in
the presence of a catalyst) can be named l-cyanoethanol.

1 34 Review and extension information
4.5b Names of saturated and unsaturated compounds
Type of compound
and bonding Notes on names Examples
saturated: name 'ends' with CH 3 CH 2 CH 3 propane
carbon atoms linked -ane or -an CH 3 CH 2 CH 2 OH propan-l-ol
by single bonds only CH 3 CHCH 2 OH propane-l,2-diol
I
OH
unsaturated:
multiple name ends with CH 3 CH=CH 2 propene
< .5b
bond between two -ene or -yne CH 3 C=CH propYl!"
carbon atoms
unsaturated: aldehydes: name
multiple bond between ends with -anal
~ °
CH -CH -C propanal
a carbon and another
3 2 ""
ketones: -anone
kind of atom; single H
bonds between carboxylic acids:
carbon atoms -anoie acid
CH 3 -C.
~
°
propanone
0
~
CH -CH -C propanoic acid
3 2 '","
OH
Note
4 3 Z ~
The compound CH z = CH - CH z - C is named but-3-enoic acid.
""
OH
The double bond between carbon atoms 3 and 4 is indicated in the
name as shown (see also 4.8i).
o

Review and extension information
135
4.6 Names of (a) all(anes, (b) all(yl groups,
and (e) other groups
4.6a Alkanes containing an unbranched chain of carbon atoms
The names and formulae of the first eight alkanes of this type are in B20.
The molecular formula of an alkane can be represented as C X H 2x + 2,
where x = number of carbon atoms.
x Name x Name x Name
1 methane 7 heptane 13 tridecane
2 ethane 8 octane 14 tetradecane
3 propane 9 nonane 19 nonadecane
4 butane 10 decane 20 eicosane
5 pentane 11 undecane 30 triacontane
6 hexane 12 dodecane 50 pentacontane
),
,6a
\ .6b
Note
1. The prefix n- is sometimes used to denote an unbranched chain. This
is not necessary in the IUPAC system.
2. Some scientific societies recommend. the use of 'punctuation' such as
CH 3 .CH 2 .CH 2 .CH 3 . The simpler method CH 3 CH 2 CH 2 CH 3 ,
recommended by the American Chemical Society, has been used in this
text.
4.6b Alkyl groups
The names of a few alkyl groups are given in D2. The name of an alkyl
group is derived from the name of the corresponding alkane.
CH 3 (CH 2 )sCH 3
decane
CH 3 (CH 2 )gCH 2 -
decyl
More generally, using the symbol R to represent an alkyl group:
RH R-
alkane
alkyl
Abbreviations are used, for instance, Me for the methyl group; CH 3 CI
can be written as Meel.
The methyl group CH 3 -, ethyl group CH 3 CH 2 -, propyl group
CH 3 CH 2 CH 2 -, and so on, are all primary alkyl groups, since they are
bonded to other groups at a primary carbon atom (see 4.3 for an
explanation of the terms primary, secondary, and tertiary carbon atoms).

136
Review and extension information
CH 3 CH 2 CH 2 CI, l-chloropropane, contains a primary propyl group. A
secondary propyl group CH 3 CHCH 3 is present in CH 3 CHCH 3 ,
I
I
CI
2-chloropropane. There are four alkyl groups containing four carbon
atoms (see, for instance, the four isomeric alcohols of molecular formula
C 4 H s O given in 4.2).
The names and abbreviations of some of these groups vary to some
,extent in British and American usage.
Alkyl groups
"t .6b
Formula and Abbre- Formula and Abbretype
Name viation type Name viation
CH 3 - methyl Me CH 3 CHzCHzCHz- butyl Bu (Bun)
primary
primary
CH 3 CHz- ethyl Et CH 3 CHzCHCH 3 s-butyl Bu'
(CzHs-)
I
secondary
primary
CH 3
I
CH 3 CH 2 CH 2 - propyl Pr (Pr n ) CH 3 -CH-CH 2 - isobutyl Bu i
primary
primary
CH 3
I
CH 3 CHCH 3 isopropyl Pri CH -C-CH t-butyl But
I
secondary
tertiary
3 I 3

Review and extension information
137
An alternative system for naming alkyl groups is sometimes used, see
below. (The complexity of organic compounds has tended to lead to the
use of more than one system in certain cases.)
Alternative
Formula Abbreviation Name name
CH 3 CHCH 3
Pri isopropyl methylethyl
I
CH 3 CH 2 CHCH 3 Bu' s-butyl I-methylpropyl
I
CH 3
I
CH 3 CHCH 2 - Bu i isobutyl 2-methylpropyl
4.6c Other groups
The examples given below are widely used.
Formula Name Formula Name
CH 2 =CH- vinyl (ethenyl) C 6 H s - phenyl
CH 2 =CH-CH 2 - allyl (prop-2-enyl) CH 3 O- methoxy
CH=C--':' ethynyl CH 3 CH 2 O- ethoxy
-CH 2
- methylene CH 3 CO- acetyl
CICH 2 - chloromethyl C 6 H s CO- benzoyl
Functional groups are given in 4.7.

138 Review and extension information
4.7 Functional groups
The term functional group is explained in C1.
4.7a Functional groups containing only carbon atoms
Series of compounds in
Group which this group occurs Example
"" /
C=C alkenes, cyc10alkenes CH 3 CH=CH 2 propene (propylene)
/ .~
-C::==C- alkynes, cycloalkynes CH 3 C::==CH propyne (methyl acetylene)
.7a Note
1. The above groups can be bonded to hydrogen, carbon, or other atoms
such as chlorine, for instance:
H H
.'" /
c=c
/ ""
H H
Cl
"" /
C=C
/ .'"
Cl
2. The benzene ring (see 4.1b) may be regarded as a particular kind of
functional group.
Cl
Cl

Review and extension information
139
4.7b Functional groups containing only atoms other than carbon
Series of compounds in
Group which this group occurs Example
-Cl (or halogenoalkanes CH 3 CH 2 CH 2 Br l-bromopropane
other
halogen)
-OH alcohols, phenols CH 3 -CH -CH 2 CH3 butan-2-ol
I
OH
OH
6
phenol
.7b
-N0 2 nitrocompounds C 6 HsNOz nitrobenzene
-NH2 primary amines CH3NH2 methylamine
-0- ethers CH3CHzOCHzCH3 diethyl ether (ethoxyethane)
-S03H sulphonic acids C 6 HsS03H benzenesulphonic acid
-SOzNHz sulphonamide C 6 HsSOzNHz benzenesulphonamide
-S02el sulphonyl chloride C 6 HsSOzCI benzenesulphonyl chloride
Note
The above functional groups are bonded to one or more carbon atoms in
each case (otherwise the compound does not belong to the particular
series). For instance
CH 3 -Cl
chloroalkane
CH 3 -O-CH 3
ether
4.7c deals with functional groups containing carbon as well as atoms of
other elements.

140 Review and extension information
4.7c Functional groups containing carbon as well as other elements
Series of compounds in Example
Group which this group occurs (IUPAC name in brackets)
0
~
-C ketones CH 3 COCH 3 acetone
"'-
(propanone)
.7c
0
~
-C aldehydes CH 3 CHO acetaldehyde
"'-
(ethanal)
H
0
~
-C carboxylic acids CH 3 C02H acetic acid
"'- (ethanoic acid)
OH
/.
-c' or salts of carboxylic acids CH 3 CO;:-Na+ sodium acetate
~. (sodium ethanoate)
0
a
~
-C acid chlorides (acyl CH 3 COCI acetyl chloride
"'- chlorides) (ethanoyl chloride)
CI
0
~
-C amides CH 3 CONH2 acetamide
"" (ethanamide)
NH 2
0
~
-C esters CH 3 C0 2 CH 2 CH 3 ethyl acetate
"'- (ethyl ethanoate)
OR
I
0
~
-C
"'-
0 acid anhydride (CH 3 CO)20 acetic anhydride
-C
~
0
/ (ethanoic anhydride)
-C=N cyanides CH 3 CN methyl cyanide

Review and extension information
141
Note
1. A special symbol is used for the formula of the functional group in
salts of carboxylic acids. (Compare formula c for benzene in 4.1b.)
o
2. The functional group of esters is given above as -Cf"
.'"
OR
R represents an alkyl group such as CH 3 - (see 4.6b). Other groups
such as phenyl groups can be present, for instance
o
f"
CH3-C '"
phenyl acetate
OC 6 Hs
3. In most of the above cases the functional group can be bonded to
either carbon or hydrogen. For instance
0 0 0 0
~ ~ ~ ~
H-C CH-c H-C CH 3 -C.
'", .'"
NH '"
3 "- 2 NH 2 H H
formamide acetamide formaldehyde acetaldehyde
(methanamide) (ethanamide) (methanal) (ethanal)
In some cases, however, particularly ketones and cyanides, the
functional group must be bonded to carbon, otherwise the compound
does not belong to the particular series (compare 4.7b). For instance
aldehydes.
o 0
~ //
is a ketone, but H - C and CH 3 - Care
'" H " H

142 Review and extension information
4.8 Names of carbon compounds
This section, 4.8, reviews the naming of compounds covered in
Chapter 1, and also deals with names of additional compounds such as
ketones, ethers, cyanides, amines, and derivatives of benzene. Trivial
names of various compounds are discussed in 4.10. (See also 4.4,
Numbering of carbon atoms.)
4.8a Compounds in Chapter 1
References below are mainly to summaries of Sections B to D.
Series of compounds References Series of compounds References
alkanes B20 halo genoalkanes B23 (3)
C28 (6) C28 (7)
4.6
alkenes C28 (4) alcohols C28 (3 and 7)
cycioalkanes and C28 (5) benzene and Dl6 (2 to 4)
related compounds
derivatives
alkynes Dl6 (1) aldehydes, carboxylic Dl6 (5 to 7)
acids, acid chlorides 4.8b and 4.8d
4.8b Aldehydes
~
Functional group - C See D 16 (5 to 7).
"- H
o
Note
1. The name benzaldehyde is generally used for C 6 H s CHO.
o 0
~ ~
2. The compound C-CH -CH -C is named butanedial.
/ 2 2 '"
H
H

Review and extension information
143
4.8c Ketones
Compound
o
~
Functional group - C The suffix -one is used to denote a ketone .
IUPAC name
."
Other names
Detailed example
propanone
acetone (dimethyl ketone)
pentan-2-one
butanone
1 2 3 4 5
ethyl methyl ketone CH 3 -C-CHz-CHz-CH 3
II
o
1 2 3 4 5
CH 3 CHzCOCH 2 CH 3
1 2 3 4 5
CH 3 COCH 2 CH 2 CH 3
pentan-3-one
pentan-2-one
diethyI ketone
methyl propyl ketone
...................... : : .
pentan-2-one
pentan:
a total of five carbon atoms
cyclohexanone
-one:
-C- group
II
o
-2-:
Carbon atom 2 forms part of
the -C- group
II
o
1 2 3 4 5
CH 3 COCH z COCH 3
pentane-2,4-dione
acetyl acetone
Note
"-
The prefix -oxo is used to denote the c=o group in compounds such
/
as CH 3 COCH 2 CH 2 C0 2 H, 4-oxopentanoic acid.

144 Review and extension information
4.8d Carboxylic acids and derivatives
See D16 (5 to 7), detailed example in D16 (6).
Functional
groups
or
0
,/.
0
~
~
-c (-C02H) -c. (-CO;) -c (-COCl)
'", "". '"
OH 0 Cl
carboxylic acid carboxylate acid chloride
'.8d
0 0 0
~ ~ ~
-C (-CONH2) -C (-C02R) -C
'"
.'" '",
NH2 OR 0
amide ester /
(R: CH 3 -, C2H s -, etc.)
-C
~ 0
acid anhydride
Examples
N arne commonly
Series Formula IUPAC name used
carboxylic acid CH 3 C02H ethanoic acid acetic acid
salt of carboxylic
acid CH 3 CO;Na+ sodium ethanoate sodium acetate
acid chloride CH 3 COCl ethanoyl chloride acetyl chloride
amide CH 3 CONH2 ethanamide acetamide
ester CH 3 C02CH2CH 3 ethyl ethanoate ethyl acetate
acid anhydride (CH2CO)20 ethanoic anhydride acetic anhydride
Note
Many trivial names of carboxylic acids and their derivatives are
commonly used, for instance: CH 3 C0 2 H, acetic acid; HC0 2 H, formic
acid; and C 6 HsC0 2 H, benzoic acid.
Further examples are in 4.10g and 4.10h.

Review and extension information
145
4.8e Ethers
Functional group - 0-
Ethers are named as substituted alkanes in the IUP AC system.
: ;' ;
i CH3CH2~CH2CH3 i
I ~.~~~~~~~~.~~.~ i
The name diethyl ether is however more commonly used for
CH3CH20CH2CH3·
4.8f Cyanides (nitriles)
Functional group -C=N
Examples of different ways of naming one of these compounds are given
below (methyl cyanide and acetonitrile are widely used).
CH 3 -C=N
methyl cyanide, acetonitrile
Gyanoethane, ethanonitrile
4.8g Amines and ammonium salts
These organic compounds are essentially derivatives of ammonia, and
simple ammonium salts, in which one or more hydrogen atoms have
been replaced by an alkyl, or similar group (see the table below). One
hydrogen atom of ammonia has been replaced by such a group in a
primary amine, two hydrogen atoms in a secondary amine, and so on.
Note'
The terms primary, secondary, and tertiary amine should be contrasted
with primary, secondary, and tertiary carbon atom and alkyl group (see
4.3 and 4.6b). The compound CH 3 CH 2 - NH -CH 2 CH 3 is a
secondary amine, because two hydrogen atoms in ammonia have been
replaced by alkyl groups. These alkyl groups, CH 3 CH 2 -, however are
primary alkyl groups. This somewhat confusing use of terms has
unfortunately become well established.
The table on the next page summarizes the names of different types of
amines.

146
Review and extension information
Functional
Compound group Example
H
I
primary amine -NH2 CH3-N-H CH3NH2 methylamine
C2Hs
I
I
secondary amine -NH C2Hs-N-H (C2Hs)2NH diethylamine
CH3
I
I
tertiary amine -N- C2Hs-N-C2Hs (C2Hs)2NCH3 diethylmethylamine
H
I
, .89
salt of primary -NHj CH -NLH ct- CH3NHjCI- methylammonium
3 I
amine
chloride
H
CH 3
I
I
salt of tertiary -NH+ CH -NLH ct- (CH3)3NH+Cl- trimethylammonium
3
amine I I
chloride
CH 3
I
CH 3
I
quaternary -NL CH -NLCH Cl- (CH3)4N+CI- tetramethylammonium
3
ammonium salt I
I 3
chloride
CH3
Note
1. The method of naming amines is somewhat exceptional. The above
names are very widely used (similarly aniline, for C 6 HsNH2, see 4.1 OJ).
Other, more systematic, methods for naming amines are illustrated
below.
CzHsNHz aminoethane, ethanamine
CH 3 CHzCHzNHz l-aminopropane, propan-I-amine
H2NCH2CH2CH2NH2 1,3-diaminopropane, propane-l,3-diamine
2. Trivial names of some amines and substituted amines are frequently
used. For example
H2NCH2(CH2)4CH2NH2 hexamethylene diamine
(systematic name, hexane-l,6-diamine); used to manufacture Nylon 66.
a
~
CH 3 CH -C alanine (systematic name 2-aminopropanoic acid);
I '" a constituent of proteins.
NHz OH
3. Note the spelling: methylamine, but methylammonium chloride.

Review and extension information
14~
4.8h Derivatives of benzene
See 4.1b (formula of benzene), D16, 2 to 4, (names of monosubstituted
derivatives of benzene) and 4.10j (trivial names of benzene derivatives).
Disubstituted derivatives of benzene
The benzene molecule is symmetrical (see model of benzene molecule,
figure 8, D2). The substitution reaction given below yields the same
compound, chloro benzene, irrespective of which hydrogen atom is
replaced.
Monosubstitution
of benzene yields only one product:
0+Cl2
catalyst)
CI
6+ Hel
chlorobenzene
C 6 H s Cl
Further substitution to give C 6 H 4 Clz can take place in three different
positions. (This does not necessarily imply that all positions are equally
likely to be attacked by chlorine during the course of an actual
reaction.) In order to distinguish between these positions the benzene
ring is numbered as shown below (the carbon atom attached to chlorine
is numbered 1).
Disubstitution of benzene can give rise to three isomeric products:
Further substitution can occur at carbon atoms:
2 or 6 3 or 5 4
ortho- meta- para-
'0'
;6, 6 :6:
Cl Cl Cl
4 4

148 Review and extension information
There are five hydrogen atoms in C 6 HsCI, but some of the carbon atoms
are geometrically equivalent. Replacement of one hydrogen atom in
chlorobenzene can occur at only three geometrically different positions,
called ortho-, meta-, and para- (abbreviated to 0-, m-, and p-
respectively). There are two geometrically equivalent ortho- positions,
two meta-~ and one para-, and therefore a total of three isomeric
dichlorobenzenes, molecular formula C 6 H 4 Cl 2 (commonly called
o-dichlorobenzene, m-dichlorobenzene, and p-dichlorobenzene). The
systematic names show which carbon atoms are bonded to chlorine.
Isomeric dichlorobenzenes, C 6 H 4 Cl 2
.Bh
CI
l,2-dichlorobenzene
(o-dichloro benzene)
1,3-dichlorobenzene
(m-dichloro benzene)
CI
1,4-dichloro benzene
(p-dichloro benzene)
Note
1. Lowest numbers are used. For example, the systematic name of
o-dichlorobenzene is 1,2-dichlorobenzene (not 1,6-). The formula of
1,2-dichlorobenzene showing hydrogen atoms is given below.
2. Substituents are generally arranged in alphabetic order, for instance
l-chloro-2-fluoro benzene.
3. Many benzene derivatives have widely-used common names (see
4.10j). In aniline, C 6 H s NH 2 , and phenol, C 6 H s OH, the amino and
hydroxyl groups are allocated the number 1 (see below).
Examples of derimtives of benzene
OH ~
~CH' O,N
9NO,
1,2-dichlorobenzene
9Br
4-bromoaniline
(p-bromoaniline)
CH 3
2,4-dimethylphenol
NOz
2,4,6-trinitrophenol
(picric acid)

Review and extension information
149
4.8i Compounds with more than one functional group
Some of the rules for naming these compounds are rather complex, but
the examples given below may help you. Consult a reference book for
further details.
Formula and name
Remarks
BrCHzCHzCHzCI
l-bromo-3-chloropropane
3 5
CH 3 CHzCH=CHC=CCH 3
hept-3-en-5-yne
4 Z
CH 3 CH=CHCHzCHOHCH 3
hex-4-en-2-o1
Alphabetic order of prefixes.
The suffix -en(e) takes 'precedence' over -yne. The
name of the compound is not hept-2-yn-4-ene.
The suffix -01 takes precedence over -ene; -01
is allocated the lowest number.
2-hydroxypropanoic
3 1
CH 3 COCHzCOzH
3-oxobutanoic acid
acid
Only one suffix must be used (-ene and -yne
can, however, be used in addition, see above).
Some groups can therefore be shown by a
prefix or suffix: hydroxy (prefix), -ot (suffix).
The prefix oxo- shows the presence of a
"
c=o group.
/
4.9 American usage of systematic nomenclature
This differs slightly from British usage, but it is usually easy to deduce
formulae from names. For example:
British
American
CH 3 CHzCHzOH propan-I-ol I-propanol
CH 3 CHzCH=CHz but-l-ene I-butene
HOCHzCHzCHzOH propane-I,3-diol 1,3-propanediol
German and French usage again differs slightly, for instance,
propanol-lor propanol(1).

1 50 Review and extension information
4.10 Trivial and other names
Systematic nomenclature is not always applied, particularly in older
books. A number of commonly used names are given in this section.
Some of these are accepted by scientific societies such as the Chemical
Society of London. No distinction is made below between these and
'unacceptable' trivial names. (Consult more detailed reference books
to check on this.) In some cases the systematic name of the compound
is given in brackets.
4.10a Names of series of compounds
paraffin (alkane) aromatic hydrocarbon (arene)
olefin (alkene) alkyl halide (halogenoalkane)
.lOa 4.10b Hydrocarbons
.10b CH 3 CH 3 CH 3
JOe I I I
CH 3 CHCH 3 CH 3 CHCHzCH 3 CH 3 CCH 3 CH 3 (CHz)3CH3
isobutane isopentane I n-pentane
CH 3
neopentane
CHz=CHz CH 3 CH=CHz CH=CH
ethylene propylene acetylene
0 &CH3
toluene m-xylene styrene
6CH,
4.10c Halogenoalkanes
CH 3 CI CH 2 Cl 2 CHCl 3 CCl 4
methyl chloride methylene chloroform carbon
chloride
tetrachloride
CH 3 CHzCH 2 CI CH 3 CHCICH 3 CHzBrCHzBr CHz=CHCI
n-propyl chloride isopropyl chloride ethylene dibromide vinyl chloride

Review and extension information
151
4.10d Alcohols
CH30H CzHsOH CH 3 CHzCHzCHzOH CH3CHzCHOHCH3
methyl alcohol ethyl alcohol n-butyl alcohol s-butyl alcohol
CH3CH(CH3)CHzOH
isobutyl alcohol
CH 3
I
CH3CCH3
I
OH
t-butyl alcohol
CH3(CHz)3CH20H
n-amyl alcohol
HOCH2CH20H
glycol, ethylene glycol
HOCH2CHOHCH20H
glycerol
4.10e Aldehydes
HCHO CH3CHO CH 3 CHzCHzCHO C 6 HsCHO
, .11
formaldehyde acetaldehyde butyraldehyde benzaldehyde
4.10f Ketones
CH3COCH3 CH3CH2COCH(CH3h C 6 HsCOCH3
acetone,
dimethyl ketone
ethyl isopropyl ketone
acetophenone
C 6 HsCOC 6 Hs
benzophenone
4.10g Carboxylic acids
HCOzH CH 3 COzH CH3CHzC02H CH3CH2CHzCOzH
formic acid acetic acid propionic acid n-butyric acid
valerie acid stearic acid benzoic acid
phenylacetic acid acrylic acid cinnamic acid
4.10h Derivatives of carboxylic acids
CH3COCl (CH3CH2COhO CH3CH2CH2CONH2
acetyl chloride propionic anhydride butyramide
CH3C02CH(CH3h CH3(CH2)14C02Na +
isopropyl acetate
sodium palmitate

152 Review and extension information
4.10i Ethers and cyanides (nitriles)
C 2 HsOC 2 Hs CH 3 0CH 2 CH 2 CH 3 CH 3 CN
diethyl ether, ether methyl n-propyl ether acetonitrile
CH 2 =CHCN
acrylonitrile, vinyl cyanide
4.1 OJ Derivatives of benzene
C 6 H s OH C 6 H s NH 2 C 6 H s CHO C 6 HsCOCH 3 C 6 HsCOC 6 Hs
phenol aniline benzaldehyde acetophenone benzophenone
m-xylene cumene salicyc1icacid acetylsalicylic acid
(aspirin)
acetanilide
NOz
p- nitroacetanilide
NOz
p-nitroaniline
OH
o-toluidine
NOz
picric acid
NOz
trinitrotoluene
(TNT)

15~
Chapter 5
Answers to review pro blems
Note
Actual answers are in ordinary type. Additional information and
explanations are in small type.
5.1 Answers to 2.1
1 Increasing boiling point: ethane, propane, butane, pentane, hexane
)
Formulae CH3CH3 CH3CHzCH3 CH3(CHzhCH3 CH3(CHz)3CH3 CH3(CHz)4CH3
(for reference) ethane propane butane pentane hexane
2 IUPAC names CH 3 CH 2 CI: chloroethane CHCI 3 : trichloromethane
3 a. 1,2-difluoroethane is more reactive than 1,l-difluoroethane.
1,2-difluoroethane contains fluorine atoms on adjacent carbons. The fluorine atoms in
l,l-difluoroethane are on the same carbon atom.
b. Structural formulae can be written in a number of different ways (see 4.lc and 3.1).
The formulae given below are all examples of correct answers. .1
F
I
1,I-difluoroethane:
CH3CHF2'
F H
I
I
F-C-C-H
I
H
I
H
CHF 2 CH 3 ,F-CH-CH 3
F H
I
I
H-C-C-H
I
F
I
H
1,2-difluoroethane: FCH 2 CH 2 F,
H H
I I
F-C-C-F
I I
H H

154 Answers to review problems
4 IUPACnames CHCI 2 CHCI 2 : I,I,2,2-tetrachloroethane
CH 3 CCI 3 : I, I, I-trichloroethane
Check your answers carefully. Examples of wrong answers, and comments:
1,2-tetrachloroethane; each substituent chlorine atom should be assigned a number.
1-1-2-2-tetrachloroethane; wrong punctuation.
I-trichloroethane; see comment about 1,2-tetrachloroethane.
1,1,l-chloroethane; prefix tri- must be used to show the presence of three chlorine atoms.
2,2,2-trichloroethane; carbon chain numbered wrongly.
5
A CH 2 CICH 2 CH 2 CI: 1,3-dichloropropane
B CH 3 CHBrCH 2 CH 2 CH 2 Br: l,4-dibromopentane
C CH 2 CICH 2 CH 2 Br: I-bromo-3-chloropropane
Check your answers carefully. Examples of wrong answers for Band c:
2,5-dibromopentane; carbon chain not numbered correctly.
l-chloro-3-bromopropane; substituents should be in alphabetic order.
1,3-bromochloropropane; each substituent should be numbered separately.
.1
6 Structural formulae
CI
I
Dichlorodifluoromethane: CCI 2 F 2 , CI 2 CF 2 , F-C- F
F
I
Bromotrifluoromethane: CBrF 3 , BrCF 3 , Br-C- F
I
F
I-bromo-I-chloro-2,2,2-trifluoroethane:
I
CI
'
CI
I
F-C-CI
I
F
BrCHCICF 3 ,
H F H F
I I I I
Br-C-C-F, CI-C-C-F
I I I I
CI F Br F
All the above are examples of correct answers.
Note
Additional exercises reviewing Section B are given in Chapter 3,3.2.
Work through these optional exercises if you think you need additional
practice, or had specific difficulties in Section B, or the review problems
in 2.1 (see the mark list opposite).

i
Answers
to review problems
155
The mark list given below may help you to decide whether you need to work through
these exercises. Allocate half marks etc. for partly correct answers. It is suggested that you
omit the exercises in 3.2 if you score 30 marks or more.
Problem 1 2 3a 3b 4 5 6
Marks 6 4 2 4 6 9 9
A1aximum 40 marks
5.2 Answers to 2.2
Note
Condensed formulae are given as answers to problems 12 and 13 (also
16 in 2.3). You may have preferred to use expanded formulae.
'" /
7 Propene contains a C=C group.
/ .'"
8
N arne and functional groups Formulae (for reference)
3-chlorohex-l-ene CH 3 CHzCHzCH - CH= CHz
'" I
/
Cl
CI, C=C
/ '"
cyclobutanol
-OH
CHz-CHz
I
I
CHz-CHOH
2-methylpentane-l,3-diol CH -CH -CH-CH-CH OH
3 z I I z
-OH OH CH 3
(two groups)
hepta-l,3-diene CH 3 CHzCHzCH = CH- CH= CHz
'" /
C=C
/ '"
(two groups)
There are six carbon atoms in 3-chlorohex-l-ene
2-methylpentane-l,3-diol.
and

156 Answers to review problems
9 A
CH 3 CHzCHzCH 3 :
butane
B
CH 3 CHCH3:
I
CH 3
Notc
An alternative name for B is methyl propane (see 4.4).
2-methylpropane.
10 c
CH 3 CHzCH==CHz:
E
CHz -
I /I
CHz-CH
CH: cyclobutene
but-l-ene
D
CHz-CHz:
I
I
CHz-CHz
cyclobutane
C is an isomer ofD, because both have the same molecular formula,
C4Hs·
~ .2
Note
1. Check your answers carefully. Examples of wrong answers for Care but-l,2-ene,
but-3-ene, but ~,4-ene, and but-2-ene (see C8).
"'- /
2. C and E have the same functional group, C=C , but are not isomers. C has
/ "'-
molecular formula C 4 Hs ; E, C 4 H 6 . Isomers are compounds with the same molecular
formula. They need not have the same functional group. Structural isomers are discussed
further in Chapter 4,4.2.
11 F
CH 3 CHzCHCH 3 :
I
OH
butan-2-o1
G
CH 3 CHCHzOH:
I
CH 3
2-methylpropan-l-ol
H CH 3
I
CH 3 - C- CH 3 : 2-methylpropan-2-o1
I
OH
Check your answers carefully. Examples of wrong answers: F, butan-3-ol;
G, 2-methylpropan-3-ol; H, l,l-dimethylethanol, trimethylmethanol. (See 4.2 for further
examples of structural isomers.)

Answers to review problems
12 Pentan-2:-ol: CH 3 CHzCHzCHCH 3
I
OH
pent-2-ene: CH 3 CHzCH=CHCH 3
Example of wrong
answer for pent-2-ene: CH 3 CHzCHzCH=CHz.
1 Z 3 4
13 Buta-l,3-diene: CHz=CH-CH=CHz
1 z 3 4
butane-l ,4-diol: HOCHzCHzCHzCHzOH
4 3 z 1
Example of wrong answer for buta-l,3-diene: CH 3 CH=C=CHz'
Answers to optional problems 14 to 16 are in 5.3.
Note
Additional exercises reviewing Section C are given in Chapter 3,3.3.
Work through these optional exercises if you think you need additional
practice, or had specific difficulties in Section C, or the review problems
in 2.2.
The mark list given below may help you to decide whether you need work through these
exercises. Allocate half marks etc. for partly correct answers. It is suggested that you omit
the exercises in 3.2 if you score 30 marks or more.
Problem 7 8 9 10 11 12 13
Marks 1 functional groups 4 3 names 6 9 4 8
carbon atoms 2 isomers 3
Maximum
40 marks
5.3 Answers to 2.3
543 Z 1
14 (a) is correct, CH 3 CHCHzCH=CHz: 4-methylpent-l-ene
I
CH 3
Note 5 4 3 Z 1
4-methylpent-2-ene has the formula CH 3 CHCH=CHCH 3
I
.....3
CH 3
157

1 58 Answers to review problems
15 Hydrogen is likely to react with H.
H: penta-l ,3-diene; J: 2-methylbuta-l ,3-diene.
H, generally represented as CH 3 -CH=CH -CH=CHz rather than
CH 3
I
CH=CH -CH=CHz, contains an unbranched (continuous) chain of fivecarbon atoms.
It is normally preferable to write this chain horizontally, but this is not always done.
CH 3
I
J, CHz=C-CH=CHz, contains a branched carbon chain.
Note
Compound J (see above for formula) is commonly called isoprene. It is formed during the
destructive distillation of natural rubber. In 1955, synthetic rubber, identical in almost
every respect to natural rubber, was prepared from isoprene. This material is generally
called polyisoprene. .
Isoprene (compound 1) is obtained from petroleum sources and this material contains
small quantities ofpenta-l,3-diene (compound H). This causes difficulties in the
preparation of polyisoprene synthetic rubber.
.3
The shape selective catalysts mentioned in this problem (see 2.3) have been used to convert
any penta-l ,3-diene (H) present to pentane; isoprene (branched carbon chain) is unaffected
by hydrogen in the presence of these catalysts. Pentane, formed from penta-l,3-diene,
does not interfere with the preparation of polyisoprene synthetic rubber.
CH 3
I
CHz'=C-CH=CHz:
2-methylbuta-I,3-diene
(isoprene)
no reaction with hydrogen in the presence of shapeselective
catalysts. Used to prepare polyisoprene.
CH 3 -CH=CH-CH=CH 3 + 2H z spec~al shape) CH3-CHz-CHz-CHz-CH3
penta-l,3-diene selectivecatalyst pentane
(impurityinisoprene)
16 CH3CH2CH(CH2)11 CH3
I
CH 3
3-methylpentadecane
CH3CH2CH2CHzCH(CHz)6CH3
I
CHzCH2CHzCH3
5-butyldodecane
CH3CH2CH2CH(CHz)sCH3
I
CH2CH2CH3
4-propy ltridecane
All three compounds have molecular formula C16H34, and are isomers ofhexadecane,
CH3(CHz)14CH3'
Pentadecane: CH3(CHzh3CH3; tridecane: CH3(CHz)l1CH3; dodecane:
CH3(CHz)lOCH3·
Propyl group: CH3CHzCHz-; butyl group: CH3CHzCHzCHz-. (See 4.6a and 4.6b.)

Answers to review problems
159
5.4 Answers to 2.4
Note
Structural formulae can often be written in a number of different ways.
Examples of alternative correct answers are therefore given in the
answers to problem 20.
The functional group in carboxylic acids is the -C0 2 H group.
18 Functional groups, decanal: -CHO (aldehyde)
cyclopentanol: - OH (hydroxyl)
"" /
octa-l,3-diene: C~C (two groups)
/ ""
oct-3-yne: -C=C-
3,3-diethylhexan-I-ol: -OH
acetylene: -C=C-
ethylene:
'" /
C=C
/ '"
Ethyl groups are not functional groups.
19 CH 3 CH 2 CHO: aldehydes CH 3 CI: chloroalkanes (halogenoalkanes)
CH 3 C-CH: alkynes CH 3 CH=CHCH 2 CH 3 : alkenes
CH 3 CH 2 0H: alcohols
20 Note
Alternative formulae are given for benzene and bromobenzene.
H H H2 H2
0
C
0
C C C 'CH
HcDCH H~r'" ~CH
2
I I I I
I 2 2 II
HC" :;;.--CH HC, ~CH H2C, ........ CH2 H2C, ........ CH
C C C C
H H H2 H2
CoHo, benzene cyclohexane cyclohexene
H c ........'yH H y ........
CH3(CH2)4C02H CH3C02H CH3CH2CH2CHCH2CH20H
I
OH
hexanoic acid acetic acid hexane-I,3-diol

160 Answers to review problems
6
Br
I
C
HCO~~CH
I I
HC" /,CH
C
C 6 HsBr, bromo benzene H
2,2,3-tribromohexane
21 a. CH 3 COCI: acetyl chloride
b. CH 3 CH==C==CHz: buta-l,2-diene
Note
Formulae of compounds mentioned in (a):
~
o
Cl-CH -C
2 '"
chloro~cetic 0H
aCid
Cl-C=C-H
chloroacetylene
~
CH 3 -C.
o
acetyl '"
chloride Cl
~
Cl-CH -C
2 '",
o
chloroacetaldehyde H
The formula of of buta-l,3-diene is given in 5.2, answer to problem 13.
22 Note
Alternative names are given in some cases, for instance for D and E.
C 6 H s OH: phenol C 6 H s CI: chlorobenzene C 6 H 6 : benzene
A B C
C 6 H s CH 2 CH 3 : ethylbenzene C 6 H s CH=CH 2 : styrene CH 3 CH 2 Br: bromo ethane
0 (phenylethane) E (vinylbenzene, F
phenylethylene)
CH 2 =CH 2 : ethene CH 3 CH 2 0H: ethanol CH 3 CHO: acetaldehyde
G (ethylene) II I (ethanal)
CH 3 C0 2 H: acetic acid CHCl 2 CHCI 2 : I, 1,2,2-tetrachloroethane CH=CH: acetylene
J (ethanoic acid) K L (ethyne)
CH 3 CHCH 3 : propan-2-ol CH 3 CH=CH 2 : propene CH 3 CH 2 CH 2 CHO: butanal
I
OH
N (propylene) 0
M
CH 3
I
CH 3 CH 2 CH 2 CH 3 : butane CH 3 CHCH 3 : 2-methylpropane CH 2 =CHCH=CH 2 : buta-l,3-diene
p Q R
CH 3 CH 3
I
I
CH 3 CH 2 CH=CH 2 : but-I-ene CH 3 -C-CH 2 -CH -CH 3 : 2,2,4-trimethylpentane
S I CH3
T

Answers to review problems
161
Answers to optional problems 23 to 27 are in 5.5.
Note
Additional exercises reviewing Section D are given in Chapter 3, 3.4.
Work through these optional exercises if you think you need further
practice, or had specific difficulties in Section D, or the review problems
in 2.4.
The mark list below may help you to decide whether you need to work through these
exercises. A satisfactory score is about 60 marks. You may find it useful to do Section 3.4
if you score less than 75 marks.
Problem 17 18 19 20 2la 2lb 22
Marks 2 14 15 16 4 4 40
Maximum 95 marks
5.5 Answers to 2.5
23 A
CBr 4: tetrabromomethane
c
CH 3 (CH 2 )sCHBrCH 2 CBr 3 :
B
CH 3 (CH 2 )sCH=CH 2 :
1,1,1,3-tetrabromononane
oct-l-ene
24
CH 3
D
I
3,3-dimethylbut-l-ene: CH 3 - C-CH==CH 2
I
CH 3
CH 3
E
I
3,3-dimethylbutan-2-01: CH 3 - C-- CH -CH 3
I
CH 3
I
OH

162 Answers to review problems
25 CH 2 -CH 2
"
CH/ II
II
CH
"" /
CH 2 -CH 2
cycloocta-I,5-diene
CH
CH
CH=CH
/' ~
/CH 2 C\2
CH2
I
I
CH
\ /
CH
~ ,/
CH 2 -CH 2
cyclododeca -1,5,9-triene
CH
CH2
CH
See answer to problem 26 for numbering of carbon atoms in this type of
cyclic compound.
.5
Note
Cyclododeca-l,5,9-triene is not a regular dodecagon as indicated by the above structural
formula. The angle between carbon-carbon bonds would then be 150°,and the molecule
would be subject to considerable strain. Two geometric arrangements, in which bond
angles are such as to minimize strain, are possible. One of these is shown below. (Build a
model of this molecule, if you can.)
CH
"
2
CH/ CH2
II
CH CH
/ ~
CH 2
CH
I
I
CH2 CH CH2
'" ~ "" /
CH CH 2
cyclododeca-I,5,9-triene
(indicating molecular shape)
I

Answers to review problems
163
26 CH=CH
/3 4""
CH 2
II
CHi
5CH
II
6CH
""8 7 /
CH=CH
cycloocta-l ,3,5,7-tetraene
(numbering of carbon atoms shown)
The structural formula of this compound shows a system of alternating
single and double bonds, similar to the formula for benzene (see answer
to problem 20 in 5.4). Willstatter wanted to prepare this compound so
that he could compare its properties with those of benzene.
Note
Willstatter found the properties of this compound to be different from those of benzene.
Theoretical considerations subsequently indicated that a compound such as
"-
cycloocta-l,3,5,7-tetraene (with a ring made up of eight CH groups) would not
;f'
resemble benzene, that is, would not be an arene (aromatic compound). It was predicted
that certain compounds with larger rings would possess aromatic character. Some of
these have been prepared recently. One compound, C 18 H 18 , contains a ring made up of
"-
eighteen CH groups. The name of this compound is [18]annulene.
;f'
The physical properties of this compound, CisH iS ' resemble those of benzene to some
extent; its chemical reactions are, however, different from those of benzene. The formula
is given below in simplified form (the ring is made up of eighteen CH groups). You
;f'
may find it interesting to build a model of this molecule.
"-
, .5'

164 Answers to review problems
27
H
I -
,C"
CH~'~1\ ". CH 3
CH 2 CH 3
F
G
Figure 15
F: l-chloro-2-methylbutane
G: 1,2-dichloro-2-methylbutane
.5
Note
CI
I
G can be represented as CICH 2 -C-CH 3 ,
I
CH 2 CH 3
CI
1 I 3 4
CICH2 - C- CH 2 CH 3 : 1,2-dichloro-2-methylbutane.
I
CH 3
or writing the longest chain horizontally
In the same way F, CICH 2 CHCH 2 CH 3 : l-chloro-2-methylbutane .
I
CH 3

165
Notes for teachers
Aims and content of the programme
This programme deals with structural formulae and systematic names
of alkanes, halogenoalkanes, alcohols, alkenes, dienes, alkynes,
cycloalkanes, cycloalkenes, aldehydes, carboxylic acids and derivatives,
benezene, and simple substituted benzenes.
The programme aims at something wider than merely correct use of
systematic nomenclature. An introduction to isomerism andfunctional
groups is included, and the use and interpretation of structural formulae
is particularly stressed; see for example: Section A (Chapter 1),
3.1 (Chapter 3), 4.1 and 4.2 (Chapter 4). Trials in schools showed that
the programme served as a useful aid for introducing organic
chemistry. One teacher, for instance, was 'very impressed with the
way the students, who had no previous knowledge or experience of
organic chemistry, handled formulae; this was very helpful when we
started Topic 9'.
A more detailed discussion of the objectives of the programme and
suggested methods of use are given below. Evaluation of the programme
indicated that it not only helped students to overcome some of the
difficulties associated with the early stages of studying organic
chemistry, but also provided some insight into scientific and
technological aspects of this subject.
Whenever possible, names and formulae are presented not in isolation,
but (with brief explanatory notes) in relation to compounds of
scientific or industrial importance. Some reactions are also included.
Examples are in B16, C23, D2 (Chapter I), 4.5a (Chapter 4), and many
of the review problems in Chapter 2 (for instance, problems 2 to 6, 22,
25, and 26). Students found that 'This approach made organic
chemistry enjoyable, easier to learn, and gave perspective to the theory
of organic chemistry.' They also found it 'interesting to know what
compounds are used for in everyday life', and occasionally were
'inspired to do a good deal of further reading into polymers, petroleum,
aromatics, and so on'.
Teachers also confirmed the usefulness of the programme for
introducing organic chemistry. One teacher, for instance, who used this
book in conjunction with the programme Ethanol and other alcohols
An introduction to the reactions of carbon compounds, thought that 'the

166 Notes for teachers
student who works through the programmes will feel more at home
with organic chemistry; able and interested pupils will pick up a good
deal of additional information, and get something of the "feel" of the
subject' .
An outline of the content of this programme is provided by the
summaries of the main sections in Chapter 1 (A7, B23, C28, D16). The
review problems in Chapter 2, optional exercises in Chapter 3, and the
review and extension information in Chapter 4, should be examined to
obtain a clearer picture of the overall scope of this text. Much
information on naming compounds is given in tabular form (see for
instance C6).
The nomenclature used in the Advanced Chemistry course follows the
recommendations of the International Union of Pure and Applied
Chemistry (IUPAC). A few non-systematic names in common use are
given. Nomenclature is also discussed in Appendix 1, Teachers' guide
II of this course, and in the Nuffield Chemistry Handbook/or teachers,
Chapter 2, pages 34 to 43. Useful reference books are: Handbookfor
Chemical Society Authors, published by the Chemical Society (1961),
and An introduction to chemical nomenclature by R. S. Cahn, published
by Butterworths (1968).
Suggested methods of use
Appendix 6 of Teachers' guide II of this course explains the structure
and development of the Nuffield Advanced Chemistry programmed
texts. Organizing the use of the programmes so that they fit into a
school course and reinforce other forms of instruction, is outlined, on
the basis of experience arising from trials in schools, on pages 332 to 336
of this appendix, in the form of questions and answers. A few points
related to this programme are dealt with in greater detail here.
This programme is suitable both as an aid for introducing Topic 9 and
for revision. In practice teachers used it mostly for introducing the topic
sometimes together with the programme Ethanol and other alcohols.
In many cases students were given the programme before, or at the
same time as starting Topic 9, and asked to complete Sections A to C in
Chapter 1 (plus the relevant review problems and, if necessary, optional
exercises) over a period of about two weeks. Section D was set at a later
stage. Many students who had no previous knowledge of organic
chemistry were able to cope with the programme as homework. Teachers

Notes for teachers
167
in general preferred to set the programme as homework, and considered
this 'constructive use of homework and saving of teaching time a
valuable feature of the programmed text'. A brief introductory talk in
class, and short periods of class discussion are useful. It is desirable to
spread the use of the programme over three or four weeks. Some
teachers arranged for this to occur at the same time as fairly lengthy
pieces of experimental work. If the programme is used for homework, it
is useful to allow students who have had no previous experience of
programmed learning to work through the first few pages in class.
Students are encouraged to use molecular models while working
through the programme to assess the relation between structural
formulae, and molecular geometry. This may present difficulties for
homework, but some work with molecular models would greatly
enhance the understanding of formulae.
The programme has been specifically designed to allow for maximum
flexibility in use with students of widely different abilities, interests, and
previous knowledge. Students with little or no previous knowledge of
organic chemistry will need to work through the main sections in
Chapter 1, but can, if they wish, omit the additional information given in
small print on the properties and importance of the compounds.
Optional remedial subsections ('frames') are available for students
requiring further help.
All students should be encouraged to work through the review problems
in Chapter 2. A marking scheme helps students to decide whether they
can proceed, or need to work through the optional exercises in Chapter
3. Many students in the trials schools in fact chose to do these exercises,
even when they had obtained high marks in the review problems. The
optional problems in Chapter 2 are intended as additional work for the
more interested and able student. For revision, students can read the
summaries, then attempt the review problems without necessarily
working through the main sections.
The review and extension information in Chapter 4 can be used as follows.
4.1 to 4.5 provide additional background information on structural
formulae, isomers, and so on. 4.6 to 4.7 (and also 4.4 to 4.5) contain
various tables and special points relating to names of alkanes, of
functional groups, and of saturated and unsaturated compounds. 4.8 to
4.10 are mainly reference sections for systematic names of different
classes of compounds, some also covered in the main sections, others

168 Notes for teachers
outside the scope of these sections. Chapter 4 is useful to students for
Topic 13as well as Topic 9.
Objectives
The wider aims of the programme, and the extent to which these were
achieved during school trials, were discussed at the beginning of these
notes.
Evaluation during trials was also directed towards more specific
objectives where achievement could be assessed in a precise and
objective manner. This type of objective is concerned with 'what the
student will be able to do after working through the programme'
(generally called behavioural objectives). Achievement is tested by means
of a post-test, in this case the review problems in Chapter 2 (2.1, 2.2, and
2.4). Teachers can assess the objectives of the programme by reference
to these problems and the corresponding answers in Chapter 5.
Examples of these objectives are given below.
After completing Sections A to D satisfactorily, the student will be
able to:
1 Relate the name of a simple alkane to the number of carbon atoms
present (problem 1).
2 Write down correct IUPAC names corresponding to given structural
formulae - alkanes (problems 9 and 22), halogenoalkanes (problems 2,
4,5, and 22), cycloalkanes (problem 10), and alcohols (problems 11
and 22).
3 Write down correct IUPAC or acceptable alternative names
corresponding to given structural formulae for simple aldehydes,
carboxylic acids, alkenes, alkynes, benzene and derivatives (problem
22). Note: See answers to problem 22 in 5.4 for examples of alternative
names.
4 Write down correct expanded or condensed structural formulae
corresponding to given names: halogenoalkanes (problems 3b, 6, and
20); alkenes (problems 12 and 13); alcohols (problems 12, 13, and 20);
cycloalkanes and cycloalkenes (problem 20); carboxylic acids
(problem 20); benzene and derivatives (problem 20).

Notes for teachers
169
5 Discriminate between correct and incorrect names corresponding to
given structural formulae (problem 21).
6 Identify the series to which a compound belongs, given its structural
formula (problems 17and 19).
7 Demonstrate awareness of the information which can be derived from
systematic names, for instance:
a functional groups presen t (pro blems 7, 8, and 18)
b number of carbon atoms present (problem 8)
c other information (problem 3a).
8 Discriminate between compounds which are isomers and those which
are not, given the corresponding structural formulae (problem 10).
Note
1 The optional problems in 2.3 and 2.5 extend some of these objectives.
2 Section A deals with certain aspects of structural formulae. The
exercises in 3.1 test and expand some of these points.
Previous knowledge
As mentioned earlier, students worked successfully through this
programme without any previous experience of organic chemistry.
Some knowledge of elementary ideas on bonding in carbon compounds
is desirable, and, although the programme includes an introduction to
structural formulae, some previous experience of writing structural
formulae of simple compounds such as methane, ethane, and
chloromethane, will help students in the initial stages.
Time taken for completing the main sections in Chapter 1
This varied between fairly wide limits as would be expected when
students are working at their own pace. On average, 15 minutes were
required to complete Section A, 40 minutes for Section B, 50 minutes
for Section C, and 60 minutes for Section D. Variations were due both
to normal differences in rates of working, and to the extent to which
optional sections were used. Times of completion for Section D, for
instance, varied between ~hour and 2 hours.