Solution
Related Formula
E = E° - 2.303RTnF QCore Logic
Reaction for the oxidation half-cell:
H₂(g) arrow 2H⁺(aq) + 2e⁻Here, n = 2.
Nernst equation:
E = E° - (0.059)/(n) [H^+]²PH₂Given parameters: [H^+] = 0.02 ~M = 2 × 10⁻² ~M PH₂ = 2 ~atm E° = 0 ~V
Step 1: Calculate E
E = 0 - (0.059)/(2) ((0.02)²)/(2) E = -0.0295 ( (0.0004)/(2) ) E = -0.0295 (2 × 10⁻⁴) E = -0.0295 ( 2 + 10⁻⁴) E = -0.0295 × (0.3010 - 4) E = -0.0295 × (-3.699) E = +0.1091 ~V ≈ 0.109 ~VPattern Recognition
Since standard potential of SHE is 0V, when oxidizing hydrogen gas into protons, lower proton concentration (<1M) and higher gas pressure (>1atm) makes the cell more spontaneous (positive E).
Chapter Mix
Class 12 Chemistry: Electrochemistry