Consider the following half-cell reactions:
I. A + e⁻ → A⁻ E° = +0.96 V
II. B⁻ + e⁻ → B²⁻ E° = −0.12 V
III. C⁺ + e⁻ → C E° = +0.18 V
IV. D²⁺ + 2e⁻ → D E° = −1.12 V
What combination of two half-cells would result in a cell with the largest potential?

Question

Consider the following half-cell reactions:

I. A + e⁻ → A⁻ E° = +0.96 V

II. B⁻ + e⁻ → B²⁻ E° = −0.12 V

III. C⁺ + e⁻ → C E° = +0.18 V

IV. D²⁺ + 2e⁻ → D E° = −1.12 V

What combination of two half-cells would result in a cell with the largest potential?

Accepted Answer

Answer: I and IV — Maximum emf obtained by combining highest and lowest reduction potentials. E°cell = 0.96 − (−1.12) = 2.08 V Half-cells I and IV.