c
\(\mathrm{Ag}_{2} \mathrm{C}_{2} \mathrm{O}_{4} \rightleftharpoons 2 \mathrm{Ag}^{+}+\mathrm{C}_{2} \mathrm{O}_{4}^{2-}\)

\(\quad \quad \quad 2.2 \times 10^{-4} \mathrm{M} \quad 1.1 \times 10^{-4} \mathrm{M}\)

\(\mathrm{K}_{\mathrm{sp}}=\left[\mathrm{Ag}^{+}\right]^{2}\left[\mathrm{C}_{2} \mathrm{O}_{4}^{2-}\right]\)

\(=\left[2.2 \times 10^{-4}\right]^{2} \cdot\left[1.1 \times 10^{-4}\right]\)

\(\mathrm{K}_{\mathrm{sp}}=5.3 \times 10^{-12}\)