Answer : The correct answer is 3.
Explanation :
The given chemical reaction is,
[tex]BrO^-_3(aq)\rightarrow Br^-(aq)+BrO^-_4(aq)[/tex]
In a disproportionate reaction, disproportionate substance is a single substance which is oxidized as well as reduced.
The oxidation state of Br in [tex]BrO^-_3[/tex] is (+5).
The oxidation state of Br in [tex]Br^-[/tex] is (-1).
The oxidation state of Br in [tex]BrO^-_4[/tex] is (+7).
In the given chemical reaction, [tex]BrO^-_3[/tex] is getting reduced to [tex]Br^-[/tex] and [tex]BrO^-_3[/tex] is getting oxidized to [tex]BrO^-_4[/tex]. So, bromine is a disproportionate substance.
That means the bromine is present in three oxidation states.
Therefore, three oxidation states of the disproportionate substance have throughout the reaction.
