JEE Main 2025 Jan 29 Shift 1, Chemistry Q21: Properties of Amines

Among the four amines, benzylamine (${\mathrm{C}}_6{\mathrm{H}}_5\mathrm{C}{\mathrm{H}}_2\mathrm{N}{\mathrm{H}}_2$) is the most basic. Its lone pair on N is fully localised (not in conjugation with the ring), unlike aniline and para-nitroaniline whose lone pairs delocalise into the ring (more so with the $-M$ $\mathrm{N}{\mathrm{O}}_2$ group), and unlike the acetanilide whose lone pair is drawn into the carbonyl.

Reaction: ${\mathrm{C}}_6{\mathrm{H}}_5\mathrm{C}{\mathrm{H}}_2\mathrm{N}{\mathrm{H}}_2+\mathrm{HCl}\to {\mathrm{C}}_6{\mathrm{H}}_5\mathrm{C}{\mathrm{H}}_2\mathrm{N}{\mathrm{H}}_3^{+}\mathrm{C}{\mathrm{l}}^{-}$ (1:1 stoichiometry).

Moles of benzylamine in 1.0 g $=\frac{1.0}{107}\approx 9.346\times 10^{-3}\mathrm{mol}.$

Moles of HCl consumed $=9.346\times 10^{-3}\mathrm{mol}$; mass $=9.346\times 10^{-3}\times 36.5\approx 0.341\mathrm{g}=341\mathbf{mg}.$