Question

What is Nernst equation? Write the relation between standard electrode potential and electrode potential.

Hint:

The Nernst equation corrects the electrode potential for non-standard conditions (other than 1 M, 1 atm, 298 K).

Answer 1

The Nernst equation gives the relation between electrode potential and the concentrations (activities) of the ions involved in the electrode reaction.
For a general half-cell reaction:
\[ M^{n+} + ne^- \;\rightleftharpoons\; M \]
The Nernst equation is:
\[ E = E^\circ - \frac{0.0591}{n} \log \frac{1}{[M^{n+}]} \]
or equivalently,
\[ E = E^\circ - \frac{0.0591}{n} \log \frac{[Ox]}{[Red]} \]
Relation:
- \(E^\circ\) = standard electrode potential (when ion concentration is 1 M).
- \(E\) = electrode potential under given conditions.
Thus, electrode potential depends on concentration, number of electrons transferred, and temperature.
\[ \boxed{E = E^\circ - \frac{0.0591}{n} \log Q} \]
where \(Q\) = reaction quotient.