The standard half-cell reduction potential for Ag+|Ag is 0.7991 V at 25°C. Given that the experimental value of Ksp = 1.56 × 10⁻¹⁰ for AgCl, calculate the standard half-cell reduction potential for the Ag|AgCl electrode.

For desired reaction, AgCl + 1e⁻ → Ag + Cl⁻
E⁰ = -ΔrG⁰/(1F)
The needed ΔrG⁰ for the reactions:
Ag⁺ + 1e⁻ → Ag; ΔG⁰ = -nFE⁰
AgCl → Ag⁺ + Cl⁻; ΔG⁰ = -RTlnKsp,
ΔrG⁰ = -(1 mol)(9.468 × 10⁴ J mol⁻¹ V⁻¹)(0.7991 V) - (8.314 J K⁻¹ mol⁻¹)(298 K)ln(1.56 × 10⁻¹⁰) = -75.61 kJ + 55.95 kJ = -19.66 kJ
The potential is E⁰ = -(-19.66 kJ)/(1)(96.485) = +0.204 V