Question

The oxidation potential of a hydrogen electrode at $pH=10$ and $P_{H_2}=1$:-

• A. $0.51V$
• B. $0.00V$
• C. $+0.59V$
• D. $0.059V$

Answer 1

The correct option is C $+0.59V$

For hydrogen electrode : $2H^{+}+2e^{-}\to H_2$

$E_{red}=E_{red}^o-\frac{0.0592}{n}log\frac{P_{H2}}{[H^{+}{]}^2}$

$E_{red}=0-\frac{0.0592}{2}log\frac{1}{({10}^{-10}{)}^2}$

$E_{red}-0.59V$

$E_{oxid}=-E_{red}=-(-0.59)=0.59V$

Note: $\left[H^{+}\right]={10}^{-pH}={10}^{-10}$