Chapter 13, Problem 10E

Among the solubility rules previously discussed is the statement: Carbonates, phosphates, borates, and arsenates—except those of the ammonium ion and the alkali metals—are insoluble.

(a) Write the expression for the equilibrium constant for the reaction represented by the equation

${\text{CaCO}}_3\left(s\right)\rightleftharpoons {\text{Ca}}^{2+}\left(aq\right)+{\text{CO}}_3{}^{2-}\left(aq\right)$. Is $K_c>1,<1$, or $\approx 1$? Explain your answer.

(b) Write the expression for the equilibrium constant for the reaction represented by the equation ${\text{3Ba}}^{2+}\left(aq\right)+2{\text{PO}}_4{}^{3-}\left(aq\right)\rightleftharpoons {\text{Ba}}_3{\left({\text{PO}}_4\right)}_2\left(s\right)$. Is $K_c>1,<1$, or $\approx 1$? Explain your answer.