Given:
Ksp(Ag2CrO4) = 1.2×10-12
Ksp(BaCrO4) = 2.1×10-10
For a solution which is initially 0.005 M in Ba2+ and 0.005 M in Ag+, it is desired to precipitate one of these ions as its chromate (CrO42-) salt to the maximum possible degree without precipitating any of the other cation. From this solution, which ion can be selectively first-precipitated by controlled addition of CrO42- and, ideally, what is the maximum possible percentage of that ion which can be exclusively so precipitated?
(Assume that there is no change in the total volume of the solution.)