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Question: A hydrogen gas electrode is made by dipping platinum wire in a solution of HCL of pH=10 and by passi...

A hydrogen gas electrode is made by dipping platinum wire in a solution of HCL of pH=10 and by passing hydrogen gas around the platinum wire at one atm pressure. The oxidation potential of electrode would be:
(a) 0.059 V
(b) 0.59 V
(c) 0.118 V
(d) 1.18 V

Explanation

Solution

Hint: From pH value of solution, we can calculate the concentration of hydrogen ions in that solution. HCl dissociates completely in a solution.

Complete step-by-step answer:
HCl solution has a pH =10
So, we can calculate the concentration of hydrogen ions in the solution by taking a negative antilog of pH.
pH=−log⁡10[H+]pH=-{{\log }_{10}}[{{H}^{+}}]
[H+]=10−pH=10−10M[{{H}^{+}}]={{10}^{-pH}}={{10}^{-10}}M
It is given that the pressure of hydrogen gas is 1 atmospheric pressure.

So the equation used is
Ecell=0.059nlog⁡(PH2)0.5[H+]{{E}_{cell}}=\dfrac{0.059}{n}\log \dfrac{{{({{P}_{{{H}_{2}}}})}^{0.5}}}{[{{H}^{+}}]}
Where Ecell{{E}_{cell}} is the electrode potential of the cell, PH2{{P}_{{{H}_{2}}}}is the pressure of hydrogen gas, nn is the number of moles, [H+][{{H}^{+}}] is the concentration of H+{{H}^{+}}.
Here, n=1 ,PH2{{P}_{{{H}_{2}}}}=1 , [H+]=10−pH=10−10M[{{H}^{+}}]={{10}^{-pH}}={{10}^{-10}}M
Substituting these values in the equation, we get
Ecell=0.0591log⁡110−10=+0.59V{{E}_{cell}}=\dfrac{0.059}{1}\log \dfrac{1}{{{10}^{-10}}}=+0.59V

Therefore, the oxidation potential of electrodes is +0.59V. The correct option is (b).

Additional Information:
Hydrogen gas electrode is also called standard hydrogen electrode as it is used as a reference electrode based on the equilibrium between aqueous protons and electrons on one side and on hydrogen gas on the other side, in a solution saturated with hydrogen gas. It is a redox electrode abbreviated as SHE. It consists of a platinized platinum electrode which is dipped in an acidic solution (usually HCl) and pure hydrogen gas is bubbled through it. The acid solution should have an activity of H+{{H}^{+}} as 1moldm−31mold{{m}^{-3}}. There is a hydroseal which prevents oxygen interference.

Note: Oxidation potential of an electrode depends on the concentration of H+{{H}^{+}} and the pressure of the hydrogen gas. It also depends on the number of moles involved.