Assertion : Reaction of ${\text{SO}}_2$ and ${\text{H}}_2\text{S}$ in the presence of ${\text{Fe}}_2{\text{O}}_3$ catalyst gives elemental sulphur.Reason : ${\text{SO}}_2$ is a reducing agent.

The reaction is $2{\text{H}}_2\text{S}+{\text{SO}}_2\to 2{\text{H}}_2\text{O}+3\text{S}$. In this reaction, ${\text{SO}}_2$ acts as an oxidizing agent (it oxidizes ${\text{H}}_2\text{S}$ to $\text{S}$). While ${\text{SO}}_2$ can act as both an oxidizing and reducing agent, here its oxidizing nature is responsible for the result. Thus, the assertion is true but the reason is false.