Redox Reactions · Question 22

Which is the best description of the behaviour of bromine in the reaction given below? H2O + Br2 HOBr + HBr

1. Proton acceptor only
2. Both oxidised and reduced
3. Oxidised only
4. Reduced only

Answer

(2) Both oxidised and reduced

Solution

Oxidation number of Br:

In Br2: 0

In HOBr: +1 + (-2) + x = 0 ⇒ x = +1 (increase ⇒ oxidation)

In HBr: -1 (decrease ⇒ reduction)

∴ Bromine is both oxidised and reduced — a disproportionation reaction.

Answer: (2)