The correct order of basicity of the following

Answer

C

Explanation

The conjugate acid obtained by addition of a proton to amine 4 is stabilized by three (I-III) equivalent resonance structures while that obtained from amine 3 is stabilized by only two (IV-V) equivalent resonance structures.

Therefore, amine 4 is more basic than amine 3. In amine 2 the lone pair of electrons is present on a `sp^(3)`-hybridized N while in amine 1 it is present on a `sp^(3)`-hybridized N. since a `sp^(2)` hybridized N is more electronegative than a `sp^(3)` hybridized N, therefore, amine 2 is less willing to donate its lone pair than amine 1. in other words, amine 2 is less basic than amine. 1. combining both the trends, the basicity of the four amines, i.e., increases in the order: `2 lt 1 lt 3 lt 4`, i.e., option (c) is correct.