Which of the following has peroxy linkage?

What is the number of allotropes of selenium?

When $H_2SO_4$ reacts with $PCl_5$,the obtained product$(s)$ is/are:

Assertion: The reaction between $SO_2$ and $H_2S$ in the presence of $Fe_2O_3$ catalyst gives elemental sulfur.
Reason: $SO_2$ is a reducing agent.

Which of the following compounds produces an $oxy$-$acid$ having a basicity of $2$ upon hydrolysis?

Choose the $INCORRECT$ statement about $SO_2$.