2H^+ (aq) + BrO2^-(aq) + BrO3^- (aq) <--> 2BrO2(aq) +H2O(I)  Like many reactions in living cells, all three reactions specified are redox reactions.  Identify the species being oxidized and...

2H^+ (aq) + BrO2^-(aq) + BrO3^- (aq) <--> 2BrO2(aq) +H2O(I)

 

Like many reactions in living cells, all three reactions specified are redox reactions.  Identify the species being oxidized and the species being reduced in the reaction.

Expert Answers
mlsiasebs eNotes educator| Certified Educator

An oxidation-reduction reaction, or redox reaction, occurs when electrons are transferred from one species to another.  You must always have a reduction and an oxidation reaction in pairs.  Neither can happen alone.

To determine what is oxidized in reduced, we first need to look at the oxidation numbers for each species

H+ --> +1 because oxidation number is the same as the charge

Br (in BrO2-) --> +3 because each oxygen is -2 and we need Br to be +3 so that the sum of the oxidation numbers equals -1

O --> -2

Br (in BrO3-) --> +5 (see note for BrO2-)

O --> -2

Br (in BrO2) --> +4 (because the sum of oxidation numbers must be zero for a neutral compound)

O --> -2

H --> +1

O --> -2

To find the reduced species, we need to find the reaction that occurs from the accepting of an electron (i.e. the oxidation number is reduced) so BrO3- is reduced to BrO2 because it goes from +5 to +4

To find the oxidized species, we need to find the reaction that occurs from the donation of an electron (i.e. the oxidation number increases) so BrO2- is oxidized to BrO2 because it goes from +3 to +4.