1.1. Bromide ions and bromate(V) ions react in acidic conditions to form aqueous bromine in the following equation.

5Br^– (aq) + BrO₃^– (aq) + 6H⁺ (aq) → 3Br₂ (aq) + 3H₂O (l)

A series of experiments was carried out at a given temperature to find the rate equation for the reaction.

The results from experiments using different hydrogen ion concentrations are shown in Fig. 2.1.

Fig. 2.1

Use the information in Fig. 2.1 to determine the order of reaction with respect to hydrogen ions.

1.2. Experiments using different bromide concentrations showed that the order of reaction with respect to bromide ions was first order. 

On the graph in Fig. 2.2, sketch a graph to show how the concentration of bromide ions would change during the course of a reaction.

Fig. 2.2

1.3. Overall, the reaction between bromide ions and bromate(V) ions in acidic conditions is fourth order.

i) Deduce the order with respect to bromate(V) ions.

ii) Using your answer to part (a) and the information in part (b), write the rate equation for the reaction.

1.4. Bromide ions and bromate(V) ions react in acidic conditions to form aqueous bromine in the following equation.

5Br^– (aq) + BrO₃^– (aq) + 6H⁺ (aq) → 3Br₂ (aq) + 3H₂O (l)

i) Using your answer to part (c), write an expression for the rate constant for the reaction between bromide ions and bromate(V) ions in acidic conditions.

ii) Suggest suitable units for the rate constant.