Consider the following statements in respect of oxides of sulphur.
$(1)$ In gas phase $SO_2$ molecule is $V$-shaped.
$(2)$ In gas phase $SO_3$ molecule is planar.
$(3)$ $\gamma-SO_3$ is a cyclic trimer.
Which of the above statements are correct?

The element which does not belong to group $15$ is

In the following, the oxoacid with a peroxy bond is

Upon heating $KClO_3$ in the presence of a catalytic amount of $MnO_2$,a gas $W$ is formed. Excess amount of $W$ reacts with white phosphorus to give $X$. The reaction of $X$ with $HNO_3$ gives $Y$ and $Z$.
$(1)$ $W$ and $X$ are,respectively:
$[A]$ $O_3$ and $P_4O_6$
$[B]$ $O_2$ and $P_4O_6$
$[C]$ $O_2$ and $P_4O_{10}$
$[D]$ $O_3$ and $P_4O_{10}$
$(2)$ $Y$ and $Z$ are,respectively:
$[A]$ $N_2O_3$ and $H_3PO_4$
$[B]$ $N_2O_5$ and $HPO_3$
$[C]$ $N_2O_4$ and $HPO_3$
$[D]$ $N_2O_4$ and $H_3PO_3$
Give the answer of question $(1)$ and $(2)$.

Write a note on the oxidation state of group-$16$ elements.

What are the products formed when ferrous sulphate $(FeSO_4 \cdot 7H_2O)$ is heated strongly?