When a colorless gas is passed through bromine water and it causes decolorization,which gas is it?

Identify the correct statements from the following:
$i$. Sulphuric acid is manufactured by contact process.
$ii$. $SO_3$ dissolves in $H_2SO_4$ to form pyrosulphuric acid $(H_2S_2O_7)$.
$iii$. $H_2SO_4$ is used in the manufacture of fertilisers such as ammonium sulphate and super phosphate.
$iv$. In the reaction,$S + 2H_2SO_4 (\text{conc.}) \longrightarrow 3SO_2 + 2H_2O$,$H_2SO_4$ is oxidised to $SO_2$.

Rhombic sulphur has the following structure:

The number of $S=O$ and $S-OH$ bonds present in peroxodisulphuric acid $(H_2S_2O_8)$ and pyrosulphuric acid $(H_2S_2O_7)$ respectively are:

Which element from the following does $NOT$ belong to the chalcogen family?

Write a note on the preparation of sulphur dioxide. Explain the properties of sulphur dioxide. State its uses.