The Nearst Equation: A galvanic cell is constructed at `25^(@)C` as follows. Once half-cell
Channel: Doubtnut
Date: 30/08/2020

The Nearst Equation: A galvanic cell is constructed at `25^(@)C` as follows. Once half-cell consists of the `Fe^(3+)//Fe^(2+)` couple in which `C_(Fe^(3+)) = 1.00 M` and `C_(Fe^(2+)) = 0.100 M`, the other involves the `MnO_(4)^(-)//Mn^(2+)` couple in which `C_(MnO_(4)^(-)) = 1.00 xx 10^(-2)M, C_(Mn^(2+)) = 1.00 xx 10^(-4) M`, and `C_Mn^(2+) = 1.00 xx 10^(-3) M`. (a) Find the elecrode potential for each half-cell with these concentrations, and (b) calculate the overall cell potential. Strategy: (a) Apply the Nernst equation to find the electrode potential of each half-cell with the given concentrations.  Write the half-reaction with the more positive (or less negative) potentikal (after correction) as the cathode reaction along with its potential. Reverse the other half-reaction (to make it anode reaction) and change the sign of its `E` value. Finally balance the electron transfer and then add the half-reactions and their electrode potentials to find the overall cell potentail.