The reaction of aniline with a mixture of concentrated $HNO_3$ and $H_2SO_4$ yields ......

Consider the following:
Statement-$I$: In the nitration of aniline,a significant amount of $m$-nitroaniline is formed.
Statement-$II$: In the presence of a strongly acidic medium,aniline is protonated to form the anilinium ion,which is meta-directing.

Which of the following is the strongest base?

Identify $Z$ in the following reaction:

The major products obtained from the following sequence of reactions are
$(CH_3)_2CHCH_2N(CH_2CH_3)_2$ $\xrightarrow{CH_3I}$ $\xrightarrow[H_2O]{Ag_2O}$ $\xrightarrow{\Delta} \text{products}$

$4$-Methylaniline on heating with alcoholic $KOH$ in the presence of chloroform gives :-