# Problem: Among the solubility rule 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 equationCaCO3(s) ⇌ Ca2+(aq) + CO3 2−(aq). Is Kc &gt; 1, &lt; 1, or ≈ 1? Explain your answer.

###### FREE Expert Solution

CaCO3(s) ⇌ Ca2+(aq) + CO3 2−(aq)

$\overline{)\mathbf{K}\mathbf{=}\frac{\mathbf{products}}{\mathbf{reactants}}}$

**solids not included

K expression for the reaction:

${\mathbf{K}}_{\mathbf{c}}\mathbf{=}\frac{\mathbf{products}}{\overline{)\mathbf{reactants}}}\phantom{\rule{0ex}{0ex}}\overline{){\mathbf{K}}_{\mathbf{c}}\mathbf{=}\mathbf{\left[}{\mathbf{Ca}}^{\mathbf{2}\mathbf{+}}\mathbf{\right]}\mathbf{\left[}{{\mathbf{CO}}_{\mathbf{3}}}^{\mathbf{2}\mathbf{-}}\mathbf{\right]}}$

Carbonates (CO32-) are insoluble except when with Group 1A ions (Li+, Na+, K+, etc.) and ammonium ion (NH4+)

###### Problem Details

Among the solubility rule 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
CaCO3(s) ⇌ Ca2+(aq) + CO3 2−(aq). Is Kc > 1, < 1, or ≈ 1? Explain your answer.