A hydrogen electrode is made by dipping platinum wire in a solution of nitric acid of pH =9 and passing hydrogen gas around the platinum wire at 1.2 ~atm pressure. The oxidation potential of such an electrode equals .V.

Step-by-step solution

For hydrogen electrode, oxidation half reaction is, 1.2 ~atm H ₂ (at pH 9) 2 H ⁺ +2 e⁻ If pH =9 then H ⁺ ion =1 10^ - pH =1 10⁻⁹ Using Nernst equation, E_ cell =E_ cell ^0- 0.0591 n [ H ⁺ ]^2 p _ H ₂ For hydrogen electrode, E_ cell ^0=0, n=2 aligned & E_ Cell =0- 0.0591 2 (10⁻⁹ )^2 1.2 & E_ Cell =- 0.0591 2 [ 10⁻¹⁸- 1.2 ] E_ Cell =+0.0531 aligned