Question

2. What is the purpose of checking for completeness of precipitation? Briefly explain how this is done.

Answer 1

The purpose of checking for the completeness of precipitation is done to verify that there are no further ions that would precipitate from the solution. This is very important in various cases where you have to remove the ions which are precipitating.

To test for the completeness of precipitation, the liquid or the remaining solution above the precipitate is taken into a separate test tube and the precipitating agent is added to it, to see whether there would be any more precipitation. If not then the earlier point was said to be point of complete precipitation.