Question

The $K_{sp}$ for a sparingly soluble ${Ag}_2{CrO}_4$ is $4\times {10}^{-12}$. The molar solubility of the salt is:

• A. $2.0\times {10}^{-6}mol{L}^{-1}$
• B. $1.0\times {10}^{-4}mol{L}^{-1}$
• C. $2.0\times {10}^{-12}mol{L}^{-1}$
• D. $1.0\times {10}^{-15}mol{L}^{-1}$

Answer 1

Answer: (B)

$1.0\times {10}^{-4}mol{L}^{-1}$

$K_{sp}$ of sparingly soluble salt ${Ag}_2{CrO}_4$ is $4\times {10}^{-12}$

${Ag}_2{CrO}_4\rightleftharpoons {2Ag}^{+}+{CrO}_4^{2-}$

initial $S$ $0$ $0$

equilibrium $0$ $2S$ $S$

$K_{sp}={\left(2S\right)}^{2}S$

$4\times {10}^{-12}={4S}^3$

$S^3={10}^{-12}$

$S={10}^{-4}$

Molar solubility of salt is ${10}^{-4}$ $mol{L}^{-1}$.