Question

Th solubilty of $Ca{\left(OH\right)}_2$ 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

The correct option is C $1.11\times {10}^{-2}$

$Ca{\left(OH\right)}_2\rightleftharpoons C{a}^{2+}\left(aq\right)+2O{H}^{-}\left(aq\right)$

$K_{sp}=S{\left(2S\right)}^2\Rightarrow 5.5\times {10}^{-6}=4S^3$

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

Hence, option (c) is correct.