${K_{sp}} = s \times {(2s)^2} = 4{s^3}$
$ = 4 \times {\left( {\frac{{0.7}}{{461.2}}} \right)^3} = 14.0 \times {10^{ - 9}}$
$(a)$ $ 10^{-10}$ $(b)$ $\frac{{Kw}}{{{{10}^{ - 10}}}}$ $(c)$ $\frac{{Kw}}{{{{10}^{ - 8}}}}$ $(d)$ $10^{-4}$