Chapter 7, Problem 7.26CP

Assume that an aqueous solution of a cation, represented as a blue sphere, is allowed to mix with a solution of an anion, represented as a red sphere, and that the following result is obtained:

Which combinations of cation and anion, chosen from the following lists, are compatible with the observed results? Explain.

$\begin{array}{ll}\text{Cations}:\hfill & {\text{Na}}^{+},{\text{Ca}}^{2+},{\text{Ag}}^{+},{\text{Ni}}^{2+}\hfill \\ \text{Anions}:\hfill & {\text{Cl}}^{-},{\text{CO}}_3{}^{2-},{\text{CrO}}_4{}^{2-},{\text{NO}}_3^{-}\hfill \end{array}$