Question

If the solubility product of $Mg{F}_2$ at a certain temperature is $1.08\times {10}^{-10}$, its solubility in mol $L^{-1}$ is _________.

• A. $7.3\times {10}^{-4}$
• B. $3.0\times {10}^{-5}$
• C. $3.0\times {10}^{-4}$
• D. $1.04\times {10}^{-5}$

Answer 1

The correct option is C $3.0\times {10}^{-4}$

Let $S$ mol/L be the solubility of $Mg{F}_2$.
The solubility product, $K_{sp}=\left[M{g}^{2+}\right][F^{-}{]}^2$
$1.08\times {10}^{-10}=S(2S{)}^2$
$S^3=2.7\times {10}^{-11}$
$S=3.00\times {10}^{-4}M$
Hence, the option C is the correct answer.