Excess of $PCl_{5}$ reacts with conc $H_{2}SO_{4}$ to give:

Which of the following compounds undergoes hydrolysis easily?

Given below are two statements:
Statement $I$: Oxygen being the first member of group $16$ exhibits only $-2$ oxidation state.
Statement $II$: Down the group $16$ stability of $+4$ oxidation state decreases and $+6$ oxidation state increases.
In the light of the above statements,choose the most appropriate answer from the options given below:

List the important sources of sulphur.

Identify the correct formula of oleum from the following.

The nature of oxide $(TeO_2)$ and hydride $(TeH_2)$ formed by $Te$ respectively are $:$