For the specific electrochemical cell , what is the primary thermodynamic driving force and effect o — Electrochemistry Chemistry Question
Question
For the specific electrochemical cell $Pt, H_2 (1\text{ atm}) \| HCl (pH = 2) \| H_2 (2\text{ atm}), Pt$, what is the primary thermodynamic driving force and effect of the differing gas pressures on the cell potential?
💡 Solution & Explanation
This specific setup defines an "Electrode Gas Concentration Cell." The electrolyte concentration ($H^+$) is uniform throughout, but the pressures of the reactant gases differ ($p_1 = 1\text{ atm}$ at the anode, $p_2 = 2\text{ atm}$ at the cathode). The cell potential is determined by the Nernst equation $E = -\frac{RT}{2F} \ln \frac{p_{anode}}{p_{cathode}}$. Thus, the pressure differential uniquely generates the non-zero EMF.