Question

The solubility of $Ca(OH{)}_2$ in water is [Given : The solubility product of $Ca(OH{)}_2$ in water $=5.5\times 10^{-6}]$

• A. $1.77\times 10^{-6}$
• B. $1.11\times 10^{-6}$
• C. $1.11\times 10^{-2}$
• D. $1.77\times 10^{-2}$

Answer 1

Answer: (C)

$Ca(OH{)}_2\rightleftharpoons C{s}^{2+}\underset{S}{(aq)}+2O{H}^{-}\underset{2S}{(aq)}$

$k_{sp}=s(2s{)}^2\Rightarrow 5.5\times 10^{-6}=4S^3$

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