Question

Give reasons for the following : Sulphur dioxide is a more powerful reducing agent in an alkaline medium than in acidic medium.

Answer 1

Sulphur dioxide is reducing agent because sulphur has d orbital so it can easily expand its oxidation state +4 to +6 and thus behave as reducing agent. in the case of TeO2, Te is a heavier element and due to inert pair effect, the Te does expand its oxidation state +4 to +6.