Which among the following group-$15$ elements does $NOT$ react with concentrated sulphuric acid?

The mixture of $B$ and $C$ are :
$NO \xrightarrow{O_2} A \rightleftharpoons D$
$A \xrightarrow{NaOH \ (aq.)} [B + C]$

Consider the following reaction:
$A +$ alkali $\rightarrow B$ (Major Product)
If $B$ is an oxoacid of phosphorus with no $P-H$ bond,then $A$ is ..... .

What is formed when ammonia reacts with excess chlorine gas?

Which of the following oxides does not give any oxyacid in aqueous solution?

Nitrogen dioxide cannot be obtained by heating: