Describe how the oxidising reactivity of the halogens $\text{Cl}_2$, $\text{Br}_2$ and $\text{I}_2$ changes down the group. Explain this pattern by referring to $E^\circ(\text{X}_2/\text{X}^-)$ values in the Data Booklet.
Write an equation to show the reaction of chlorine with water.
Use standard electrode potential, $E^\circ$, data from the Data Booklet to calculate the $E^\circ_{\text{cell}}$ for the reaction below: $ \text{Cl}_2 + 2\text{OH}^- \rightleftharpoons \text{Cl}^- + \text{ClO}^- + \text{H}_2\text{O} $
The $[\text{OH}^-]$ was increased and the $E_{\text{cell}}$ was measured. Show how the measured $E_{\text{cell}}$ would compare with the $E^\circ_{\text{cell}}$ calculated in (ii) by putting one tick (✓) in the table. Explain your answer.
An alkaline solution of chlorate(I), $\text{ClO}^-$, may be used to oxidise bromide ions to bromate(V) ions. Use the Data Booklet and the half-equation shown to write an equation for this reaction. Given half-equation: $\text{BrO}_3^-(aq) + 3\text{H}_2\text{O}(l) + 6e^- \rightleftharpoons \text{Br}^-(aq) + 6\text{OH}^-(aq)$
Calculate the $E^\circ_{\text{cell}}$ for the reaction in (i).
When a concentrated solution of bromic(V) acid, $\text{HBrO}_3$, is heated, it decomposes to give bromine, oxygen and water only. Write an equation for this reaction. Oxidation numbers may help.