Answer to Question #140290 in Physical Chemistry for Shramith

Question

Write nernst equation for Zn and Cu electrode considering both behave as metal metal ion electrode

Answer 1

The overall reaction is:

Zn(s) + Cu²⁺(aq) --> Zn²⁺(aq) + Cu(s)

At 298K, the Nernst equation in general can be represented as

$E_{cell}=E^0_{cell}-\frac{0.0591V}{n}logQ$ .

In this case $n=2$ as there are 2 electrons transferred in the cell reaction, and

$Q=\frac{[Zn^{2+}]}{[Cu^{2+}]}$. Therefore, the overall equation is:

$E_{cell}=E^0_{cell}-\frac{0.0591V}{2}log\frac{[Zn^{2+}]}{[Cu^{2+}]}$