Question

The decreasing order of basicity of the following amines is :

• A. $(I)>(III)>(IV)>(II)$
• B. $(II)>(III)>(IV)>(I)$
• C. $(III)>(I)>(II)>(IV)$
• D. $(III)>(II)>(I)>(IV)$

Answer 1

Answer: (D)

Basicity $\propto$ electron pair intensity on nitrogen.
(III) Refer image .1 No resonance and $+I$ effect from both sides $\therefore$ most basic.
(II) Refer image.2 Nitrogen do not involve in resonance $\therefore$ more basic.
(I) Refer image.3 Nitrogen lone pair is involved in resonance.
Therefore less available for donation. . . less basic.
(IV) Refer image. 4
$6\pi e^{-}$, Aromatic nitrogen lone pair participating in aromaticity $\therefore$ less available for donation.
$\therefore$ least basic.
$\therefore$ III > II > I > IV (Basicity order)