Question

What is the solubility of $PbSO_4$ in 0.01 M $Na_2SO_4$ solution if $K_{sp}$ for $PbSO_4$ is $1.25 \times 10^{-9}$ ?

• A. $1.25 \times 10^{-7} mol L^{-1}$
• B. $1.25 \times 10^{-9} mol L^{-1}$
• C. $1.25 \times 10^{-10} mol L^{-1}$
• D. $0.10\, mol\, L^{-1}$

Answer 1

Answer: (A)

$\left[SO_{4}^{2-}\right]=0.01 mol L^{-1}$
$K_{sp}=\left[pb^{2+}\right]\left[SO_{4}^{2-}\right]$
or $\left[pb^{2+}\right]=K_{sp} \left[SO_{4}^{2-}\right]$
$=\frac{1.25\times10^{-9}}{0.01}$