Chemistry - Electrochemistry Question with Solution | TestHub

${\mathrm{E}}_{\mathrm{C}{\mathrm{r}}^{3+}/\mathrm{C}{\mathrm{r}}^{2+}}^{\mathrm{o}}=-0.41$$\mathrm{V}$
${\mathrm{E}}_{\mathrm{M}{\mathrm{n}}^{3+}/\mathrm{M}{\mathrm{n}}^{2+}}^{\mathrm{o}}=+1.57$$\mathrm{V}$
${\mathrm{E}}_{\mathrm{F}{\mathrm{e}}^{3+}/\mathrm{F}{\mathrm{e}}^{2+}}^{\mathrm{o}}=+0.77$$\mathrm{V}$
${\mathrm{E}}_{\mathrm{C}{\mathrm{o}}^{3+}/\mathrm{C}{\mathrm{o}}^{2+}}^{\mathrm{o}}=+1.97$$\mathrm{V}$
Reducing nature or tendency to get oxidized$\propto -{\mathrm{E}}_{\mathrm{r}\mathrm{e}\mathrm{d}}^{\mathrm{o}}$
As more negative value of${\mathrm{E}}_{\mathrm{r}\mathrm{e}\mathrm{d}}^{\mathrm{o}}$indicates better reducing agent thus easily oxidized so oxidation of$\mathrm{C}{\mathrm{r}}^{2+}$to$\mathrm{C}{\mathrm{r}}^{3+}$is the easiest.
Reducing nature for these metals is as follows Cr > Fe > Mn > Co.