2004 AIPMT Redox ReactionsDisproportionation Reactions Easy Question 28 of 30 in Redox Reactions

Which is the best description of the behavior of bromine in the reaction given below:- $H_2O + Br_2 \rightarrow HOBr + HBr$

A Both oxidized and reduced
B Oxidized only
C Reduced only
D Proton acceptor only

The answer is A.

Solution

Oxidation state of Br in $Br_2$ = 0.
In HOBr: H = +1, O = –2, so Br = +1. Bromine has been oxidised (0 to +1).
In HBr: H = +1, so Br = –1. Bromine has been reduced (0 to –1).
The same element is simultaneously oxidised and reduced. This is a disproportionation reaction.
So bromine is both oxidised and reduced.

Concept Oxidation states in disproportionation

Redox Reactions in past papers

30 questions from this chapter have appeared across 19 exam years.