Question

The solubility of $A{g}_{2}S$ is:

$[K_{sp}=256\times {10}^{-6}]$

• A. $4\times {10}^{-2}$
• B. $4\times {10}^{-3}$
• C. $0.4\times {10}^{-2}$
• D. $0.4\times {10}^{-3}$

Answer 1

The correct option is A $4\times {10}^{-2}$

Let solubility of $A{g}_{2}S=$ $x$ moles/L
$A{g}_{2}S\rightleftharpoons 2A{g}^{+}+S^{--}$
$\therefore k_{sp}=\left[A{g}^{+}{]}^2\right[S^{--}]=(2x{)}^2\left(x\right)$
$\therefore k_{sp}=4x^3$
Given $k_{sp}=256\times {10}^{-6}$
or $256\times {10}^{-6}=4x^3$
or $x=\sqrt[3]{3\frac{256\times {10}^{-6}}{4}}$
$\therefore x=4\times {10}^{-2}$