Question

The value of $K_{sp}$ of $HgCl_2$ at room temperature is $4 \times 10^{-15}$. The concentration of $Cl^-$ ion in its aqueous solution at saturation point is

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

Answer 1

Answer: (A)

Let solubility of salt $HgCl _{2}$ is $S$.
$HgCl _{2} \rightarrow Hg ^{+2}+2 Cl ^{-}$
Its solubility product
$=(2 S )^{2}( S )=4 S ^{3}=4 \times 10^{-15}$
So, concentration of $Cl ^{\ominus}$ ion $=1 \times 10^{-5}$