# A galvanic cell which makes use of the following reaction at 298K. $Cr_2O_7^{2-}+14H^++6Fe^{2+}\rightarrow 2Cr^{3+}+6Fe^{3+}+7H_2O$.Given : $E^{\large\circ}(Cr_2O_7^{2-},H^+,Cr^{3+}|Pt)=1.33V;E^{\large\circ}(Fe^{3+},Fe^{2+}|Pt)=0.77V$.Within the cell,it is important to prevent mixing or direct contact of

$\begin{array}{1 1}Cr_2O_7^{2-},Fe^{2+}\\Cr^{3+},Fe^{2+}\\H_3O^+,Fe^{3+}\\Cr_2O_7^{2-},Cr^{3+}\end{array}$

Answer : $Cr_2O_7^{2-},Fe^{2+}$
Within the cell,it is important to prevent mixing of $Cr_2O_7^{2-}$ and $Fe^{2+}$ as they will directly combine.