Core Reactions: Redox

Core Reactions: Redox

Slide 30 of 42

Disproportionation Reaction

For example, Iodine undergoes both oxidation and reduction in the following reaction:

I2 (s) + OH – (aq) ® I – (aq) + IO – (aq) + H2O (l)

–In changing to I –, iodine undergoes reduction; oxidation state goes from ‘0’ to ‘1–’.

–In changing to IO –, it undergoes oxidation; oxidation state goes from ‘0’ to ‘1+’.

Another example:

S2O32– (aq) + 2H+(aq) à SO2(g) + H2O(l) + S(s)

Yet another one is the decomposition of hydrogen peroxide (into water and oxygen) in the presence of a catalyst (MnO2). Can you see why?

–As a matter of fact, decomposition reaction where one of the products is an element can be classified as disproportionation reaction.