Question

The potential of hydrogen electrode is $-118.5$ mV. The $H^{+}$ concentration of the solution is:

• A. $0.01$ M
• B. $2$ M
• C. ${10}^{-4}$ M
• D. $1$ M

Answer 1

The correct option is A $0.01$ M

Given:

$E=-118.5mV=118.5\times {10}^{-3}V$

We know that,

$E_{cell}=\frac{0.0591}{n}\log \left[H^{+}\right]$

Here,

$n=1$

So,

$\log \left[H^{+}\right]=\frac{-118.5\times {10}^{-3}}{0.0591}$

$\log \left[H^{+}\right]=-2.0051$

$\left[H^{+}\right]=0.01M$

Hence, this is the required answer.