Special Procedure For Limit Test Of Chloride And Sulphate For Potassium Permanganate

 

Aim: To perform special procedure for chloride and sulphate for sulphate for potassium permanganate

Principle:

Potassium permanganate produces deep voilet or purple colour solution in water which will mask the turbidity or turbidity produce by the sample. So boil the potassium permanganate  with alcohol which convert the sample to MnO2 precipitated and Potassium sulphate. The MnO2 is filtered out and the filtrate is taken for limit test for chloride and sulphate.

Procedure:

Dissolve 1.5 g of sample in 50 ml of distilled water, heat on water bath and add gradually 6 ml of ethanol ( 95%), cool dilute to 60 ml with distilled water and filtered. The filtrate is colorless and taken for limit test.

For chloride

Standard Color	Sample color
Pipette out 1ml of 0.05845% w/v of standard NaCL solution in a clean   Nessler's cylinder. Add 10ml of dilute Nitric acid and make up the volume up to 50 ml by adding distilled water. Add 1 ml of 0.1M silver nitrate and allow to stand for 5 min.	40 ml of above solution is taken in a clean Nessler's cylinder. Add 10ml of dilute Nitric acid. Add 1ml of 0.1M Silver nitrate and allow to stand for 5min.

Comparison

Compare the sample turbidity with standard by viewing the Nessler's cylinder against white back ground

For sulphate

Standard Color	Sample color
Pipette out 1ml of 0.1089% w/v of standard potassium sulphate solution in a clean Nessler's cylinder and dilute to 25ml with distilled water. Add 2ml of dilute HCl and 5ml Barium Sulphate reagent. Make up the volume up to 50 ml by adding distilled water. Allow to stand for 5 min.	10 ml of above solution is taken in a clean Nessler's cylinder. Add 2 ml of dilute HCl and 5ml of Barium Sulphate reagent. Make up the volume up to 50 ml by adding distilled water. Allow to stand for  5min.

Comparison

Compare the sample turbidity with standard turbidity by viewing the Nessler's cylinder against white back ground.

Observation & Report:

1. When viewed transversely against a dark background, the turbidity produced in the sample (KMnO4) is less /more than the standard turbidity . Hence the given sample passes/ fails the limit test for chloride.
2. When viewed transversely against a dark background, the turbidity produced in the sample (KMnO4) is less/than more than the standard turbidity. Hence the given sample passes/fails the limit test for Sulphate.