Question

How much will the potential of a hydrogen electrode change when its solution initially at $pH=0$ is neutralised to $pH=7$?

• A. Increase by $0.059V$
• B. Decrease by $0.059V$
• C. Increase by $0.41V$
• D. Decrease by $0.41V$

Answer 1

The correct option is D Decrease by $0.41V$

$H^{+}+e^{-}\to \frac{1}{2}{H}_2$

$E=0-\frac{0.0591}{1}pH$

$E_1=0$ at $pH=0$

At $pH=7$,

$E_2=-0.0591pH=-0.0591\times 7$

$=-0.41V$.