FINAL REPORT

nitrate, all this steps same, but instead of Segnetov’s salt and Nessler reagent use sulfophenol.
And need to boil in ceramics cup after add the reagent until to see its color.
6. Determination of acidity (HCO - 3 and CO 2- 3 )
Methodology
Acidity of soil is determined by titration sulfuric acid, using methyl orange and
phenolphthalein indicators.
Materials
0.05N sulfuric acid
0.01% Methyl orange indicator
0.1% Phenolphthalein indicator
Burette
Conical flasks
Experimental procedure
Weigh 20g of fresh soil from which stones, twigs and larger materials have been removed and
place in a beaker or wide-neck bottle. Add 40ml of laboratory water and stir vigorously on a
magnetic stirrer if one is available, or manually. Allow to stand for 30 min and filter through
filter paper. Determine the acidity of the filtrate by filtration with sulfuric acid or hydrochloric
acid. Measure 10ml of the sample into a conical flask add 4 drops of phenolphthalein
indicator. The color of the solution should turn magenta. If it does not, determine bicarbonate.
Titrate with 0.05N H 2 SO 4 until the pink color just disappears and record the amount of titrant
used. This value will be used to calculate the carbonate acidity.
Add 3 drops of methyl orange indicator. The sample should turn yellow. Titrate with 0.05N
H 2 SO 4 until the color just turns orange.
7. Determination of content chloride ion
Methodology
Method of determining chloride in water is by means of precipitation titration with AgNO 3 ,
also called argentometric titration. The method for chloride involves the direct titration of
chloride with AgNO 3 , using potassium chromate as an indicator. Reaction of AgNO 3 with
chloride precipitates silver chloride:
Ag + +Cl - →AgCl(s)
At the end point, excess of silver ions react with chromate to precipitate silver chromate
which has a distinctive reddish-brown color:
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