Question

What is reduction potential of hydrogen gas electrode when pure hydrogen gas is at 1 atmospheric pressure and platinum electrode is in contact with HCl solution of pH 1 at 298 K?

• A. -0.1184 V
• B. -0.0592 V
• C. -0.0296 V
• D. -0.592 V

Hint:

For Hydrogen electrode: $E = -0.059 \times pH$.

Answer 1

The Correct Option is B

Step 1: Concept
Use the Nernst equation for the hydrogen electrode: $2H^{+} + 2e^{-} \rightarrow H_{2}$.

Step 2: Formula
$E_{red} = E^{\circ} - \frac{0.0592}{n} \log \frac{P_{H_{2}}}{[H^{+}]^{2}}$. At standard conditions for $H_{2}$, $E_{red} = -0.0592 \times pH$.

Step 3: Analysis
- pH = 1. - $E_{red} = -0.0592 \times 1 = -0.0592~V$.

Step 4: Conclusion
Hence, the reduction potential is -0.0592 V. Final Answer: (B)