The elements $N$,$P$,$As$,$Sb$,and $Bi$ belong to which group?

$A$ tetra-atomic molecule $(A)$ on reaction with excess oxygen produces substance $(B)$. $(B)$ is a dehydrating agent. The substances $(A)$ and $(B)$ respectively will be:

The nature of the two oxides of nitrogen,$X$ and $Y$,formed in the reaction of sodium nitrite $(NaNO_2)$ with hydrochloric acid $(HCl)$ is:

In what way can it be proved that $PH_3$ is basic in nature?

$PH_3$ forms bubbles when passed slowly in water but $NH_3$ dissolves. Explain why?

When chlorine reacts with a gas $X,$ an explosive inorganic compound $Y$ is formed. Then $X$ and $Y$ will be