Tertiary amine oxide in which one of the alkyl group contains β-hydrogen on heating to 423-473 K eliminates a molecule of dimethyl hydroxylamine to give an alkene. This what is the major product in the following reaction?

Aniline reacts with mixed acid (conc. ${\mathrm{HNO}}_3$ and conc. ${\mathrm{H}}_2{\mathrm{SO}}_4$ ) at $288\mathrm{ }\mathrm{K} \text{to give} \mathrm{P}\mathrm{ }(51 \%),\mathrm{ }\mathrm{Q}\mathrm{ }\left(47\mathrm{\%}\right) \text{and} \mathrm{R}\mathrm{ }\left(2\mathrm{\%}\right)$ . The major product(s) of the following reaction sequence is (are)

What will be the major product in the following mononitration reaction?

The major product of the following reaction is:

The major product obtained in the following reaction is:

The nitrogen cycle is given below. Identify A and B in it.

The major product formed in the reaction given below will be :

Study the following illustration of nitrogen cycle and identify $\mathrm{A}, \mathrm{B}$ and $\mathrm{C}$ in it.