Calcium oxalate is considerably less soluble than magnesium oxalate, MgC2O4, which Ksp=8.6x10-5. Kidney stones often contain in soluble calcium oxalate CaC2O4, which has Ksp = 2.3 x 10-9. Assume a solution contained both Ca2+ and Mg2+ at a concentration of.10M
What pH would be needed to achieve maximum separation of these ions by precipitation of CaC2O4 if the solution also contains the oxalic acid H2C2O4 at a concentration of .10M?