Question

Consider the change in oxidation state of Bromine corresponding to different emf values as shown in the diagram below:

Answer 1

This your question lacks important information but I would like to give you some highlight about it.

This question is testing the idea is electrochemistry as well as redox reactions and in some books it is referred to as competition processes.

So it requires you to consider the change in oxidation state of Bromine corresponding to different electromotive force, emf values as per the diagram.

So all you need to do is to calculate E°cell corresponding to each compound under going disproportionation reaction.

If the reaction for which E°cell comes out +ve is spontaneous.