We have a solution that contains 0.022 M Ca2+ and 0.014 M Mg2+. We will use potassium hydroxide to selectively precipitate one of the ions, while leaving the other ion in solution. Since Ksp of Mg(OH)2 = 6.3*10^-10 and ksp of Ca(OH)2 = 6.5*10^-6. Mg(OH)2 will precipitate out first.
A) What minimum concentration of KOH is needed to begin precipitation of Mg(OH)2?
B) What molarity of Mg(OH)2 remains in solution at the point when the second ion begins to precipitate?
c) When potassium hydroxide runs out and we have to use potassium carbonate instead. Will potassium carbonate be a good titrant to use for selective precipitation?