Question

The solubility product of a sparingly soluble salt AB at room temperature is $1.21\times {10}^{-6}$, its molar solubility is:

• A. $1.1\times {10}^{-3}{\text{mol L}}^{-1}$
• B. $1.21\times {10}^{-6}{\text{mol L}}^{-1}$
• C. $1.01\times {10}^{-3}{\text{mol L}}^{-1}$
• D. $1.1\times {10}^{-4}{\text{mol L}}^{-1}$

Answer 1

The correct option is A $1.1\times {10}^{-3}{\text{mol L}}^{-1}$

$AB\rightleftharpoons A^{+}+B^{-}$
$SSS$
$\Rightarrow$ Solubility product $=S\times S=S^2$
$\Rightarrow S=\sqrt{K_{sp}}=\sqrt{1.21\times {10}^{-6}}=1.1\times {10}^{-3}{\text{mol L}}^{-1}$