Question

The hydrogen electrode is dipped in a solution of $pH$ = 3 at ${25}^{\circ }C$. The potential would be:
(Take $\frac{2.303\times RT}{F}=0.059V)$

• A. 0.177 V
• B. 0.087 V
• C. 0.059 V
• D. - 0.177 V

Answer 1

The correct option is D - 0.177 V

Given,
$pH=3$
$\Rightarrow -log\left[H^{+}\right]=3$
$\Rightarrow \left[H^{+}\right]={10}^{-3}$
We know,
$E_{red}=E_{red}^0+0.059log\left[ion\right]E=0+0.059log{10}^{-3}E=+0.059\times (-3)=-0.177V$