Question

Increasing order of basic strength among given compounds is-

• A. I > II > III > IV
• B. IV > III > I > II
• C. IV > I> III > II
• D. III > II > IV >I

Answer 1

Answer: (B)

Its conjugate acid do not undergo proper solvation and hence its stability decreases. Hence,basic strength decreases.

$\Rightarrow$ Lone pair is in resonance.

$\Rightarrow$ Steric inhibition(two methyl groups present at ortho position pushes nitrogen out of the plane of the benzene ring and prevents resonance of lone pair) takes place in resonance. (Basic strength increases).