Question

The value of $K_{sp}$ for $Hg{Cl}_2$ is $4\times {10}^{-15}$. The concentration of ${Cl}^{-}$ ion in its aqueous solution at saturation point is:

• A. $1\times {10}^{-5}M$
• B. $4\times {10}^{-15}M$
• C. $8\times {10}^{-15}M$
• D. $2\times {10}^{-5}M$

Answer 1

Answer: (D)

$2\times {10}^{-5}M$

$HgC{l}_2\rightleftharpoons H{g}^{2+}+2C{l}^{-}$

$S$ $2S$

$K_{sp}=\left[H{g}^{2+}\right]\left[C{l}^{-}\right]=\left[S\right][2S{]}^2=4S^3=4\times {10}^{-15}$

So $S={10}^{-5}$

Concentration of $C{l}^{-}$ in its aqueous solution is $2\times {10}^{-5}.$