Question

The reduction potential of hydrogen electrode at is
A) $ - 0.059V$
B) $ - 0.59$ $V$
C) $0.59$ $V$
D) $0.0$ $V$

Answer 1

Hint:The ability of an electrode to gain electrons is called its reduction potential.
The electrode potential is called oxidation potential and reduction potential means oxidation potential, if oxidation takes place at the electrode. Reduction involves gain of electrons.

Complete step by step solution:
Hydrogen electrode is based on the redox half reaction that happens at a platinized platinum electrode .The electrode is dipped in an acidic solution and pure hydrogen gas is bubbled through it . The concentration of both the reduced form and oxidized form is maintained as unity.
Only platinum is used because hydrogen can rapidly be adsorbed as well as inert metal and does not contribute to redox reaction during cell operation.
Here given $PH$is$10$.
Using formula $\left[ {{H^ + }} \right] + = {10^{ - PH}}$
So ${H^ + } = {10^{ - 10}}$
Now electrode potential will be
${H^ + }M$${H^ + } + {e^ - } \to \dfrac{1}{2}{H_2}$
Using the formula value of ${E^0}$$ = $$0$
${E_{cell}} = {E^0} - 0.591\log \dfrac{{\left[ {{H_{_2}}} \right]}}{{{H^ + }}}$
${E_{cell}} = - 0.59 V$
From the above equation we find that option B is correct.

Note: The standard hydrogen electrode with short form SHE is a redox electrode which forms the basis of the thermodynamic scale of oxidation-reduction potentials. A standard electrode potential has zero value , which set up the basis one needs to calculate cell potentials using different electrodes or different concentrations.