Oxidation of alcohols, hydrolysis of halogenoalkanes and ... - Pearson

Answers:
LEVEL: AS
CHEMISTRY – Organic chemistry
11. Oxidation of alcohols, hydrolysis of halogenoalkanes and classification of
reacting species (15 minutes)
(a) Potassium dichromate(VI) in aqueous sulphuric acid oxidizes propan-1-ol to two different
products depending upon the reaction conditions. Draw the full structural formula of each
product and state the reaction conditions required.
Product 1:
(1 mark)
Structural formula:
Conditions:
Distil off product as it forms.
Product 2:
(1 mark)
Structural formula:
Conditions:
Reflux mixture to complete oxidation.
(b) Give the systematic name and structural formula of the alcohol that potassium
dichromate(VI) in aqueous sulphuric acid would oxidize to propanone.
Systematic name of the alcohol: propan-2-ol
(1 mark)
Structural formula: CH 3 CH(OH)CH 3
(1 mark)
Copyright © Pearson Education Limited 2001 1

Answers:
LEVEL: AS
CHEMISTRY – Organic chemistry
(c) 1-iodobutane and 1-chlorobutane both form butan-1-ol upon hydrolysis.
(i) State the name of the reagent you would use to carry out the hydrolysis.
(1 mark)
Aqueous sodium hydroxide
(ii) Explain, in terms of bond energies, why the iodo- compound hydrolyses more readily than
the chloro- compound.
(1 mark)
The C–I bond is longer and weaker than the C–Cl bond and therefore more easily broken.
(d) (i) Explain the meaning of the following terms.
Nucleophile:
(1 mark)
A molecule or an ion that has an atom capable of donating a pair of electrons to form a dative covalent
bond with an atom in an electrophile.
Free radical:
(1 mark)
A short-lived atom or group of atoms having an unpaired valence electron.
(ii) Put a tick () in the appropriate box of the following table to classify each of the species as
nucleophile, electrophile or free radical.
(3 marks)
species nucleophile electrophile free radical
Cl +
·CH 3
OH –
Copyright © Pearson Education Limited 2001 2

Answers:
LEVEL: AS
CHEMISTRY – Organic chemistry
(e) Athletes are banned from using the steroid, 19-nortestosterone, C 18 H 26 O 2 , an illegal drug
known as nandrolone, whose structure can be written as:
(i) Name and give the formula for the functional groups in the molecule that contain oxygen.
(2 marks)
functional group 1 functional group 2
name: hydroxyl or alcohol carbonyl
formula: –O–H >C=O
(ii) Explain why nandrolone would be expected to react with bromine.
(2 marks)
Bromine would undergo an addition reaction with the C=C double bond or a substitution reaction with
the CH 3 methyl group.
(Total marks 15)
ANSWERS
Copyright © Pearson Education Limited 2001 3