Question

1)Sodium sulfate is slowly added to a solution containing 0.0500 M Ca2 (aq) and 0.0220 M Ag (aq). What will be the concentration of Ca2 (aq) when Ag2SO4(s) begins to precipitate? Solubility-product constants, Ksp, can be found here.(1.20x10^-5)
What percentage of the Ca2 (aq) can be precipitated from the Ag (aq) by selective precipitation?

2) Suppose a solution contains 0.24 M Pb2 and 0.49 M Al3 . Calculate the pH range that would allow Al(OH)3 to precipitate but not Pb(OH)2. The Ksp values for Al(OH)3 and Pb(OH)2 can be found here.