The table gives the standard redox potentials for a number of half reactions. Use it to answer the questions that follow: a) (i) Relative to which half-cell reaction are the above electrode potentials

Here's the solution to question 21:

21. (a) The table gives the standard redox potentials for a number of half reactions. Use it to answer the questions that follow:-

• $\text{Zn}^{2+}(aq) + 2\text{e}^- \rightleftharpoons \text{Zn}(s)$ $\text{E}^\circ = -0.76 \text{ V}$
• $\text{Fe}^{2+}(aq) + 2\text{e}^- \rightleftharpoons \text{Fe}(s)$ $\text{E}^\circ = -0.44 \text{ V}$
• $\text{I}_2(s) + 2\text{e}^- \rightleftharpoons 2\text{I}^-(aq)$ $\text{E}^\circ = +0.54 \text{ V}$
• $\text{Fe}^{3+}(aq) + \text{e}^- \rightleftharpoons \text{Fe}^{2+}(aq)$ $\text{E}^\circ = +0.77 \text{ V}$
• $\text{Ag}^+(aq) + \text{e}^- \rightleftharpoons \text{Ag}(s)$ $\text{E}^\circ = +0.88 \text{ V}$

a) (i) Relative to which half-cell reaction are the above electrode potentials expressed?
The standard electrode potentials are expressed relative to the Standard Hydrogen Electrode (SHE).

a) (ii) Calculate the e.m.f of the cell made up by combining the $\text{I}_2(s)/2\text{I}^-(aq)$ electrode and $\text{Zn}^{2+}(aq)/\text{Zn}(s)$ electrode.

Step 1: Identify the standard electrode potentials for the given half-cells.
$\text{E}^\circ(I_2/\text{