Consider the cell $\mathrm{Pt}\left(\mathrm{s}\right)\left|{\mathrm{H}}_2( \mathrm{s})\left(\mathrm{latm}\right)\right|{\mathrm{H}}^{+}\left(\mathrm{aq},\left[{\mathrm{H}}^{+}\right]=1\right)\left|\right|{\mathrm{Fe}}^{3+}\left(\mathrm{aq}\right),{\mathrm{Fe}}^{2+}\left(\mathrm{aq}\right)\mid Pt\left(\mathrm{s}\right)$

Given: ${\mathrm{E}}_{{\mathrm{Fe}}^{3+}/{\mathrm{Fe}}^{2+}}°=0.771 \mathrm{V}$ and ${\mathrm{E}}_{{\mathrm{H}}^{+}/\frac{1}{2}{\mathrm{H}}_2}°=0 \mathrm{V}, \mathrm{T}=298 \mathrm{K}$

If the potential of the cell is $0.712 \mathrm{V}$ the ratio of concentration of ${\mathrm{Fe}}^{2+}$ to ${\mathrm{Fe}}^{3+}$ is
(Nearest integer)