The order of basic strength in gas phase of the following compound would be:

 $\begin{array}{l}{\text{i) C}}_{\text{2}}{\text{H}}_{\text{5}}{\text{NH}}_{\text{2}}\text{,}\\ {\text{ii) (C}}_{\text{2}}{\text{H}}_{\text{5}}{\text{)}}_{\text{2}}\text{NH,}\\ {\text{iii) (C}}_{\text{2}}{\text{H}}_{\text{5}}{\text{)}}_{\text{3}}\text{N}\mathrm{and}\\ {\text{iv) CH}}_{\text{3}}{\text{NH}}_2.\end{array}$

In the reaction sequence

X and Y are, respectively,

The major product of the following reaction is:

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

The major product obtained in the following reaction is:

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