$K_{sp}$ of $M{\left(OH\right)}_2$  is $5\times {10}^{-16}$  at ${25}^{0}C$  . The pH of its saturated solution at ${25}^{0}C$  is

$\begin{array}{l}{K}_{sp}=4s^3=5\times {10}^{-16}\\ s=5\times {10}^{-6}\\ \left[\stackrel{-}{OH}\right]=2s={10}^{-5}\\ pH=9\end{array}$