Using the standard electrode potential, find out the pair between which redox reaction is not feasible.

1. Fe3+ and I-

2. Ag+ and Cu

3. Fe3+ and Cu

4. Ag and Fe3+

Hint: ${\mathrm{E}}_{\mathrm{cell}}^{\mathrm{o}}$ value must be positive

Calculate the value of ${\mathrm{E}}_{\mathrm{cell}}^{\mathrm{o}}$ for every options as follows:
(1)

This reaction is feasible since $\mathrm{E}{°}_{\mathrm{cell}}$ is positive.

(2)

This reaction is feasible since $\mathrm{E}{°}_{\mathrm{cell}}$ is positive.

(3)

This reaction is feasible since $\mathrm{E}{°}_{\mathrm{cell}}$ is positive.

(4)

This reaction is not feasible since $\mathrm{E}{°}_{\mathrm{cell}}$ is negative