To perform the limit test for chloride in a given sample of sodium acetate.

 Experiment

OBJECT: - 

To perform the limit test for chloride in a given sample of sodium acetate.

REFERENCE

Parle A., "Pharmaceutical Chemistry 1 Laboratory Manual", CBS Publishers and Distributors Pvt. Ltd., Ed Ist, 2008, pp 59

REQUIREMENTS: -

 Chemical required: sodium acetate, dilute nitric acid, 0.1 M silver nitrate solution, etc.

Apparatus required: - Measuring cylinder, glass rod, and Nessler’s cylinder, Beaker.

THEORY:

Limit tests are quantitative or semi-quantitative test designed to identify and control a small number of impurities which are likely to be present in the substance. This test involves the reaction of silver nitrate with soluble chloride to form the ppt. of silver chloride which is insoluble in dilute HNO3. The extent of the precipitation depends upon the amount of silver chloride formed i.e. on the number of chloride ions present in the substance. The opalescence produced in the test solution is compared with a reference/standard solution under the same experimental conditions.

Cl- + AgNO3 → AgCl ↓ (ppt) + NO3

PROCEDURE

Standard - 

10 ml of chloride standard solution is taken in Nessler’s cylinder. Mix it with 5 ml of

water. Add 10 mL of Dil. HNO3 Make up the volume up to 50 ml with distilled water. Now add 1mL of silver nitrate to this solution. Stirrer the solution with glass road and allow to stand for 5 minutes.

Test:

Dissolve a specified quantity of substances as per I.P. monograph in 10mL of distilled water.

Add 10 mL of Dil. Nitric acid. Makeup the volume up to 50 mL with tap water. Now add 1mL of silver nitrate to this solution. Stirrer the solution with glass road and allow to stand for 5 minutes.

OBSERVATION:

The opalescence of the test solution is less/more than the standard solution. If the opalescence of

the test solution has been less than the standard opalescence, the sample will pass the limit test.

RESULT

The limit test for chloride was performed.