Question

E^∘ for the cell, Zn|Zn²+(aq)||Cu²+(aq)|Cu is 1.10V at 25^∘C. The equilibrium constant of the reaction Zn + Cu²+(aq) rightleftharpoons Cu + Zn²+(aq) is of the order of

• A. 10⁻37
• B. 10³7
• C. 10⁻17
• D. 10¹7

Hint:

A large positive E^∘ corresponds to a very large equilibrium constant.

Answer 1

The Correct Option is B

Step 1: Relation between E^∘ and equilibrium constant: log K = (nF E^∘)/(2.303RT) 
Step 2: For the given cell reaction: n = 2, E^∘ = 1.10V At 25^∘C (T=298K): log K = (2 × 96485 × 1.10)/(2.303 × 8.314 × 298) ≈ 37 
Step 3: K ≈ 10³7