Limit test for sulphate

this presentation on limit test for sulphates is very helpful for the diploma and bachelor pharmacy students. this includes principle procedure reaction and observation of limit test.

1. LIMIT TEST FOR SULPHATE Shikha Agrawal B.Pharm : Naraina Vidyapeeth Group Of Institution

2. PRINCIPLE Limit test for sulphate is based upon reaction between barium chloride and soluble sulphates in the presence of dilute hydrochloric acid. Turbidity obtained in test solution will compared with the standard sulphate solution . This results in the precipitation of sulphates as a Barium Sulphates. Barium sulphates precipitate will form the solution turbid.

3. REACTION Na2So4+ BaCl2 BaSo4 + 2NaCl HCl Soluble sulphates Precipitate Note : HCl is used to prevent precipitation of other acid radicals. In the presence of HCl only sulphates precipitate .

4. Barium sulphate reagent is used in reaction. Barium sulphate reagent contains 1. Barium chloride 2. Sulphate free alcohol 3 .Potassium sulphate in water Potassium sulphate is used to increase the sensitivity of reaction. It reacts with barium chloride and forms Barium Sulphate in small quantity which act as a seeding agent. .

5. PROCEDURE TEST SOLUTION STANDARD SOLUTION Dissolve specified quantity of test substance in distilled water and transfer it to a nesseler cylinder Dissolve specified quantity of standard substance in distilled water and transfer it to a nesseler cylinder Add 2 ml of dil. Hydrochloric acid . Add 2 ml of dil. Hydrochloric acid. Volume makeup to 45ml with water . Volume makeup to 45ml with water . Add 5 ml of barium sulphate reagent Add 5 ml of barium sulphate reagent Stir with a glass rod and allow to stand for 5 mins . Stir with a glass rod and allow to stand for 5 mins . Observe the turbidity produced and compared with the standard solution. Observe the turbidity produced and compared with the test solution.

6. OBSERVATION The turbidity produced in the test solution will be compared with the standard solution, should be less than the standard to pass the limit test. If the turbidity obtained in test solution is less than the standard solution, sample passes the limit test and vice versa.

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