Question

Arrange the following.

In decreasing order of basic strength

Answer 1

Aliphatic amines are more basic than aromatic amines. Therefore CH₃CH₂NH₂ and CH₃NH₂ are more basic. Among the ethylamine and methylamine. ethylamine was experienced more +I effect than methylamine and hence ethylamine is more basic than methylamine.

Nitro group has a powerful electron-withdrawing group and they have both – R effect as well as – I effect. As a result, all the nitro anilines are weaker bases than aniline. In P-nitro aniline

both – R effect and – I effect of the NO₂ group decrease the basicity. Therefore decreasing order of basic strength is,

Ethylamine > Methylamine > Aniline > p-nitro aniline