Ethyl amine on acetylation gives

The final product $(IV)$ obtained in the reaction sequence
Toluene $\xrightarrow[{2. \ H^{+}}]{{1. \ KMnO_4/OH^{-}}} I$ $\xrightarrow{{SOCl_2}} II$ $\xrightarrow{{NH_3}} III$ $\xrightarrow{{OBr^{-}}} IV$ is

Primary amines react with nitrous acid to yield

Nitrobenzene on reduction with zinc and $NH_4Cl$ gives:

Ammonolysis of alkyl halides followed by treatment with $NaOH$ solution can be used to prepare primary,secondary,and tertiary amines. The purpose of $NaOH$ in the reaction is:

Which of the following is most reactive towards electrophilic substitution reaction?