Question

State with reasons, whether sulphur dioxide is acting as an oxidizing agent or a reducing agent in each of the following reactions:

•2H2S(g) + SO2(g) -> 2H2O(l) + 3S(s)

•SO2(g) +H2O(l) +NaClO(aq) -> NaCl(aq) + H2SO4(aq)

Answer 1

Answer:

A) oxidizing agent is SO2

B) NaClO is the oxidizing agent

Explanation:

A) This is a redox reaction in which oxidation and reduction occur simultaneously.

Thus, in 2H2S(g) + SO2(g) -> 2H2O(l) + 3S(s);

H2S is reduced as follows;

H2S → S + 2H+ + 2e−

We can see that SO2 has been reduced while H2S gets oxidized since it has changed state from - 2 to 0 . Thus sulphur dioxide is the oxidizing agent.

B) SO2(g) + H2O(l) + NaClO(aq) -> NaCl(aq) + H2SO4(aq)

In this, SO2 undergoes oxidation and NaClO is the oxidizing agent