Assuming that hydrogen behaves as an ideal gas, what is the EMF of the cell at 25°C if P1 = 600 mm a — Electrochemistry Chemistry Question

💡 Solution & Explanation

For a hydrogen gas concentration cell, the overall reaction is $H_2 (P_1) \rightarrow H_2 (P_2)$. The Nernst equation is $E = -\frac{0.06}{2} \log \frac{P_2}{P_1} = -0.03 \log \frac{420}{600} = -0.03 \log(0.7) = -0.03 \log(\frac{7}{10}) = -0.03(\log 7 - 1)$. Substituting $\log 7 = 0.85$ gives $E = -0.03(0.85 - 1) = -0.03(-0.15) = +0.0045$ V.