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

Explanation

In sulphur dioxide `(SO_(2))` and hydrogen peroxide `(H_(2)O_(2))`, the oxidation states of sulphur and oxygen are +4 and -1 respectively. Since they can increase as well as decrease when these compound take part in chemical reactions they can act as oxidising as well as reducing agents. For example,

In ozone `(O_(3))`, the oxidation stare of oxygen is zero while in nitric acid `(HNO_(3))` ,the oxidation state is nitrogen is +5 Since both them can undergo decrease in oxidation state and not an increase in its value they can act only as oxidising agents and not as reducing agents