Sulphur dioxide and hydrogen peroxide can act as an oxidising as well as a reducing agents in their reactions, while ozone and nitric acid act only as an oxidants. Why?

Sulphur dioxide and hydrogen peroxide can act as an oxidising as well

1.	Sulphur dioxide and hydrogen peroxide can act as an oxidising as well as a reducing agents in their reactions, while ozone and nitric acid act only as an oxidants. Why?
Answer» Solution :(a) `SO_(2)` : In `SO_(2)`, oxidation NUMBER of S is +4. Oxidation number of S ranges from -2 to +6. Therefore, in `SO_(2)` oxidation number of S can vary. S can acts as an oxidation agent or as a reducing agent. (b) `H_(2)O_(2)` : In `H_(2)O_(2)` oxidation number of O is -1. GENERALLY minimum oxidation number of oxygen is -2 and maximum oxidation number of oxygen is 0. (Exception : In `O_(2)F_(2)` oxidation number of oxygen is +1.) So, oxidation number of oxygen of `H_(2)O_(2)` is increasing by -1 to 0 and decreases by -1 to -2. So, `H_(2)O_(2)` act as oxidising agent and reducing agent. ( c) `O_(3)` : Oxidation number of oxygen in `O_(3)` is zero. Here oxidation number of oxygen reduced from zero to -1 or -2. Therefore, it acts as an oxidizing agent. (d) `HNO_(3)` : Nitrogen is `HNO_(3)` oxidation number is +5. Therefore, its oxidation number it can only decreased. Therefore, `HNO_(3)` can only used as an oxidizing agent.