Question

A hydrogen electrode is immersed in a solution with pH$=0$(HCl). By how much will the potential(reduction) change if an equivalent amount of NaOH is added to the solution? (Take $P_{H_2}=1$ atm) T$=298$K.

• A. Increase by $0.41$ V
• B. Increase by $59$ mV
• C. Decrease by $0.14$ V
• D. Decrease by $59$ mV

Answer 1

The correct option is A Increase by $0.41$ V

Electrons exchange number $=1$

By Nernst equation,

$E=E^0-\frac{2.303RT}{nF}log\frac{{10}^0}{10+7}$ $pH$ $HCl=0$

$=E^0-\frac{-0.0591}{1}log{10}^{-1}$ $pH$ $NaOH=7$

$=E^0-0.413V$

$\Rightarrow$ change in potential $=E^0-E=0.41V$ increase.