While sulphue dioxide and hydrogen peroxide and act as oxidising as well as reducing agents in their reactions, ozone and nitric acid act only as oxidants. Why?

Explanation

In sulphur dioxide sulphur is in +4 oxidation state. It can increase its oxidation number upto +6 while acting as reducing agent and can decrease its oxidation number upto either 0 or -2 while acting as oxidising agent.
Similarly in hydrogen peroxide oxidation number of oxygen is -1. It can increase its oxidation number upto zero and can decrease its oxidation number to -2.
Therefore `SO_(2)andH_(2)O_(2)` can act as oxidising and reducing agents in their reactions.
In ozone the oxidation number of oxygen is zero. It can only decrease its oxidation number but cannot increase its oxidation number. This is because it is only the most electronegative atom next to filuorine.
In nitric acid oxidation state of nitrogen is +5. It cannot increase its oxidation state because it is the maximum oxidation state of nitrate. It can only decrease its oxidation number.
Because of these reasons ozone and nitric acid can act only as oxidising agents.