Arrange the following in increasing order of their basic strength `CH_(3)NH_(2) (I),(CH_(2)NH (II),(CH_(3))_(3)N(III),C_(6)H_(5)CH_(2)NH_(2)(IV)` .

Options

A. `IV lt III lt II lt I`
B. `IV lt III lt I lt II`
C. `I lt II lt III lt IV`
D. `IV lt I lt II lt III`

Answer

B

Explanation

In the gaseous phase, basicity increases as the +I-effect of the alkyl groups increases, i.e., `CH_(3)NH_(2)(I) lt (CH_(3))_(2) NH lt (CH_(3))_(3) N (III).` However, due to -I-effect of the `C_(6)H_(5)-` group, `C_(6)H_(5)CH_(2)NH_(2)(IV)` is even a weaker base than `CH_(3)NH_(2)(I)`. thus, the overal , basic character increases in the order: `IV lt I lt II lt III`.