Question

most basic among : aniline , p-nitro aniline , benzylamine , acetanilide

Answer 1

With increase in availability of loan pair of electron, basicity increases. Among benzyl amine and aniline, benzylamine is more basic. Basicity of p-nitro aniline and acetanilide is less than benzyl amine and aniline. This is because the presence of electron withdrawing group reduces the availability of lone pair of electron on nitrogen. Electron withdrawing CO group is directly attached with nitrogen in acetanilide. Thus it is less basic than p-nitro aniline.

Thus basicity order is Benzylamine > Aniline > p-nitro aniline > acetanilide