Question

What is Nernst equation for the potential of an electrode?

Answer 1

For a general redox half cell reaction:

\[\ce{Mn^n+ + ne- <=> M_{(s)}}\]

Nernst equation: \[\ce{E = E{^{\circ}} - \frac{0.0591}{n} log \frac{1}{[Mn^{n+}]}}\]

Or more commonly written as:

\[\ce{E = E{^{\circ}} + \frac{0.0591}{n} log [Mn^{n+}]}\]

Where,

E = Electrode potential at a given concentration

E° = Standard electrode potential

n = Number of electrons involved in the reaction

[Mⁿ⁺] = Molar concentration of metal ion in solution

0.0591 is the value of \[\ce{\frac{2.303 RT}{F}}\] at 298 K.

The nernst equation becomes:

\[\ce{E = E{^{\circ}_{cell}} - \frac{0.0591}{n} log \frac{[Reduction]}{[Oxidation]}}\]

This equation is used extensively to calculate the electrode potential under varying ion concentrations and to determine the cell potential and feasibility of redox reactions.