Chemistry - Ionic Equilibrium Question with Solution | TestHub

$K_{sp}=s^2=(5\times 10^{-4}{)}^2=2.5\times 10^{-7}$.

In 0.05 M ${\mathrm{Na}}_2{\mathrm{SO}}_4$: $\left[{\mathrm{SO}}_4^{2-}\right]\approx 0.05$ (the contribution from ${\mathrm{SrSO}}_4$ is negligible).

$s=\frac{2.5\times 10^{-7}}{0.05}=5\times 10^{-6}mol/d{\mathrm{m}}^3$, which is 5 in units of $10^{-6}mol/d{\mathrm{m}}^3$.

Answer: 5.