Chapter 7, Problem 101E

Hard water often contains dissolved ${\text{Ca}}^{2+}$

and ${\text{Mg}}^{2+}$

ions. One way to soften water is to add phosphates. The phosphate ion forms insoluble precipitates with calcium and magnesium ions, removing them from solution. Suppose that a solution contains aqueous calcium chloride and aqueous magnesium nitrate. Write molecular, complete ionic, and net ionic equations showing how the addition of sodium phosphate precipitates the calcium and magnesium ions.