From each the following values of water solubility (S), evaluate the solubility product: \text { (a) } \mathrm{M}_{\mathrm{g}}\left(\mathrm{PO}_{4}\right)_{2}, \mathrm{~S}=\mathbf{6 . 1} \times \mathbf{1 0}^{-5} \mathrm{M} \text { (b) FeS, }

S=6.3 \times 10^{-9} M \text { (c) } \mathrm{Zn}_{\mathrm{\{}}\left(\mathrm{PO}_{4}\right) 2, \mathrm{~S}=1.6 \times 10^{-7} \mathrm{M} \text { (d) } \mathrm{CuF}_{2}, \mathrm{~S}=7.4 \times 10^{-5} \mathrm{M}