Chemistry - Ionic Equilibrium Question with Solution | TestHub

Given that,

The solubility product of $\mathrm{Ca}{\left(\mathrm{OH}\right)}_2$ in water $=5.5\times {10}^{-6}$

$\mathrm{Ca}{\left(\mathrm{OH}\right)}_2\rightleftharpoons \underset{\mathrm{s}}{{\mathrm{Ca}}^{2+}\left(\mathrm{aq}\right)}+\underset{2\mathrm{s}}{2{\mathrm{OH}}^{-}\left(\mathrm{aq}\right)}$

${\mathrm{k}}_{\mathrm{sp}}=\mathrm{s}{\left(2 \mathrm{s}\right)}^2\Rightarrow 5.5\times {10}^{-6}=4 {\mathrm{s}}^3$

$4{\mathrm{s}}^3=5.5\times {10}^{-6}$

$\mathrm{s}={\left(\frac{5.5}{4}\right)}^{1/3}\times {10}^{-2}$
$\mathrm{s}=1.11\times {10}^{-2}$