Answer
The solubility of $PbSO_4$ in this solution will be equal to : $1 \times 10^{-7}M$
Correct answer: $(a)$
Work Step by Step
1. Write the $K_{sp}$ expression:
$ PbS{O_4}(s) \lt -- \gt 1S{O_4}^{2-}(aq) + 1Pb^{2+}(aq)$
$2.5 \times 10^{-8} = [S{O_4}^{2-}]^ 1[Pb^{2+}]^ 1$
$2.5 \times 10^{-8} = (0.25 + S)^ 1( 1S)^ 1$
2. Find the molar solubility.
Since 'S' has a very small value, we can approximate: $[S{O_4}^{2-}] = 0.25$
$2.5 \times 10^{-8}= (0.25)^ 1 \times ( 1S)^ 1$
$2.5 \times 10^{-8}= (0.25)^ 1 \times ( 1S)^ 1$
$2.5 \times 10^{-8}= 0.25 \times ( 1S)^ 1$
$ \frac{2.5 \times 10^{-8}}{0.25} = ( 1S)^ 1$
$1 \times 10^{-7} = S$
