Q1(i). Zinc–copper cell from two half-reactions

Answer in brief

Cell Zn(s) | Zn²⁺(aq) || Cu²⁺(aq) | Cu(s); reaction Zn + Cu²⁺ → Zn²⁺ + Cu; E°cell = 1.113 V; ΔG° < 0, spontaneous.

Key points

• The couple with the lower E° (Zn) is the anode; the higher (Cu) is the cathode.
• Total (n = 2): Zn(s) + Cu²⁺(aq) → Zn²⁺(aq) + Cu(s).
• E°cell = E°cathode − E°anode = 0.350 − (−0.763) = 1.113 V.
• ΔG° = −nFE° = −(2)(96485)(1.113) = −214.8 kJ mol⁻¹ ⇒ spontaneous.
• log K = 2(1.113)/0.05916 = 37.63, K ≈ 4.2 × 10³⁷: reaction goes to completion.