Question

The cell reaction involving the quinhydrone electrode is given above:
What will be the electrode potential at $pH=3$?

• A. $1.48V$
• B. $1.20V$
• C. $1.10V$
• D. $1.30V$

Answer 1

The correct option is A $1.48V$

Given Data : 1) Standard Electrode Potential = $E^{\circ }$ =$1.30$ $volt$

2) $pH$ =$3$

To Find : Electrode Potential = $E$ = ?

We know that,

$E$ = $E^{\circ }$ - $\frac{0.059}{2}$ $log$ [$H$${}^{+}$${}^2$]

Substituting the given values we get,

$E$ = $1.30$ - $0.059$ (- $pH$) ..............(2 and 2 gets cancelled and $log\left[H^{+}\right]$ is $-\left(pH\right)$

$\therefore$ $E$ =$1.30-(-0.059\times 3)$

$E$ = $1.48$ $volt$

Hence the correct option is 'A'.