Draw a labelled diagram to show the standard electrode potential of a half-cell containing chlorine gas and chloride ions can be measured.

In the presence of acid, the manganate($\mathrm{VII}$) ion is a powerful oxidising agent. The half-equation for its reduction in acid solution is:

${{\mathrm{MnO}}_4}^{-}\left(\mathrm{aq}\right)+8{\mathrm{H}}^{+}+5{\mathrm{e}}^{-}\stackrel{ }{\rightleftharpoons }{\mathrm{Mn}}^{2+}\left(\mathrm{aq}\right)+4{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right): {\mathrm{E}}^{°}=+1.51 \mathrm{V}$

Explain why the presence of an acid is necessary for the ${{\mathrm{MnO}}_4}^{-}\left(\mathrm{aq}\right)$ to function as an oxidising agent.

In the presence of acid, the manganate($\mathrm{VII}$) ion is a powerful oxidising agent. The half-equation for its reduction in acid solution is:

${{\mathrm{MnO}}_4}^{-}\left(\mathrm{aq}\right)+8{\mathrm{H}}^{+}+5{\mathrm{e}}^{-}\stackrel{ }{\rightleftharpoons }{\mathrm{Mn}}^{2+}\left(\mathrm{aq}\right)+4{\mathrm{H}}_2\mathrm{O}\left(\mathrm{l}\right): {\mathrm{E}}^{°}=+1.51 \mathrm{V}$

Give two reasons for${{\mathrm{MnO}}_4}^{-}\left(\mathrm{aq}\right)$ acting as an oxidising agent in acidic solution.

Liquid bromine is added to an aqueous solution of potassium iodide. The following reaction takes place:

 ${\mathrm{Br}}_2\left(\mathrm{l}\right)+2{\mathrm{I}}^{-}\left(\mathrm{aq}\right)\stackrel{ }{\stackrel{ }{\rightleftharpoons }}2{\mathrm{Br}}^{-}\left(\mathrm{aq}\right)+{\mathrm{I}}_2\left(\mathrm{aq}\right): {\mathrm{E}}^{°}=+0.53 \mathrm{V}$

Write two half-equations for this reaction.