Chemistry - Electrochemistry Question with Solution | TestHub

The strongest oxidizing agent is the one that is most easily reduced, meaning it has the highest reduction potential. The given potentials are oxidation potentials. We need to consider the reverse reactions (reduction).

${\left[\mathrm{Fe}(\mathrm{CN}{)}_6\right]}^{3-}+{\mathrm{e}}^{-}\to {\left[\mathrm{Fe}(\mathrm{CN}{)}_6\right]}^{4-};{\mathrm{E}}^{\circ }=+0.35\mathrm{V}$

${\mathrm{Fe}}^{3+}+{\mathrm{e}}^{-}\to {\mathrm{Fe}}^{2+};{\mathrm{E}}^{\circ }=+0.77\mathrm{V}$

${\mathrm{Fe}}^{3+}$ has the higher reduction potential, thus it is the strongest oxidizing agent.