Answer to Question #55744 in General Chemistry for jocelyn

Question

How do you test for complete precipitation of the sulfate?
How do you know when the precipitation of sulfate is completed?

Answer 1

Sulfates are usually precipitated in the form of BaSO₄ using BaCl₂.
When during the test all the formed BaSO₄ is settled add an other drop of BaCl₂ solution.
If there will be any “cloudiness” around this drop, sulfate precipitation process is not finished.
If the solution stays clear – no additional precipitate is formed and sulfate precipitation process is completed.