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 the electrode would be:

The solution of HCl has pH=10
Hence, [H+] = 10⁻pH = 10⁻¹⁰ M
The half-cell reaction is:
H₂ → 2H⁺ + 2e⁻
The Nernst equation for this half-cell reaction is:
E = E° - (RT/2F)ln([H⁺]²/P(H₂))
At standard conditions (298K, 1 atm pressure), E° = 0V, R = 8.314 J/mol.K, T = 298K, F = 96485 C/mol.
Substituting the values:
E = 0 - (8.314 * 298 / (2 * 96485))ln((10⁻¹⁰)²/1)
E = - (0.01285)ln(10⁻²⁰)
E = - (0.01285) * (-20 * 2.303)
E = 0.5916 V
Therefore, the oxidation potential of the electrode is approximately 0.59 V.