Which of the following amines acts as the strongest base?

If aniline is treated with a $1:1$ mixture of conc. $HNO_{3}$ and conc. $H_{2}SO_{4}$,$p$-nitroaniline and $m$-nitroaniline are formed in nearly equal amounts. This is due to:

In the carbylamine reaction,the number of moles of $KOH$ and $CHCl_3$ used per mole of isocyanide produced are $X_1$ and $X_2$ respectively. Find out $X_1 - X_2$.

The increasing order of reactivity of the following compounds towards reaction with alkyl halide is:

Identify the secondary amine from the following.

The compound $X (C_{7}H_{9}N)$ reacts with benzene sulphonyl chloride to give $Y (C_{13}H_{13}NO_{2}S)$ which is insoluble in alkali. The compound $X$ is