Chemistry - Electrochemistry Question with Solution | TestHub

The ${\mathrm{E}}_{{\mathrm{M}}^{+3}/{\mathrm{M}}^{2+}}^{\circ }$ values for $\mathrm{Cr},\mathrm{Mn},\mathrm{Fe}$ and Co are $-0.41,+1.57,+0.77$ and $+1.97\mathrm{V}$ respectively. For which one of these metals the change in oxidation state form $+2$ to $+3$ is easiest?