Question

The reduction potential of hydrogen electrode at 25°C in a neutral solution is (P$_{H_2}$ = 1 bar)

• A. 0.059 V
• B. -0.059 V
• C. -0.413 V
• D. 0.0 V

Hint:

Use Nernst equation: $E = E^\circ - 0.059 \cdot \text{pH}$ for hydrogen electrode under non-standard pH.

Answer 1

The Correct Option is C

The standard hydrogen electrode (SHE) has a potential of 0 V only at pH = 0. In a neutral solution (pH = 7), we apply the Nernst equation: $E = 0 - 0.059 \cdot \text{pH} = -0.059 \cdot 7 = -0.413$ V