Standard electrode potential for $\mathrm{Sn}^{4+} / \mathrm{Sn}^{2+}$ couple is $+0.15 \mathrm{~V}$ and…
Standard electrode potential for $\mathrm{Sn}^{4+} / \mathrm{Sn}^{2+}$ couple is $+0.15 \mathrm{~V}$ and that for the $\mathrm{Cr}^{3+} / \mathrm{Cr}$ couple is $-0.74 \mathrm{~V}$. These two couples in their standard state are connected to make a cell. The cell potential will be: