 Solution

The more negative standard reduction potential identifies iron as the species more readily oxidized. Combining $\mathrm{Fe}\to \mathrm{F}{\mathrm{e}}^{2+}+2{\mathrm{e}}^{-}$ with $\mathrm{S}{\mathrm{n}}^{2+}+2{\mathrm{e}}^{-}\to \mathrm{Sn}$ gives the spontaneous standard galvanic cell reactionThe electron balance is two per reaction, and the activities of the pure metals are unity.