Which of the following compounds contains an $S - S$ bond?

There is no $S-S$ bond in

Permono sulphuric acid is known as

Which of the following elements exhibits the highest property of catenation?

Observe the following reactions:
$P_4 + 8SOCl_2 \longrightarrow 4PCl_3 + 4SO_2 + 2S_2Cl_2$
$P_4 + 10SO_2Cl_2 \longrightarrow 4PCl_5 + 10SO_2$
In both the reactions,a common product '$x$' is obtained. The number of lone pair of electrons on the central atom of '$x$' is:

Describe the manufacture of $H_2SO_4$ by the contact process.