Question

Which of the following statements is correct (i) N,N-dimethylaniline is only slightly more basic than aniline (ii) 2,6-Dimethy1-N,N-dimethylaniline is much more basic than 2,6-dimethylaniline (iii) 4-cyanonaniline (iv) 3,4,5-Trinitroaniline is more basic than 4-cyano-3,5 dinitroaniline .
A. (i),(iii)
B. (i),(ii),(iii),(iv)
C. (i),(ii),(iii)
D. (ii),(iv)

Answer 1

Correct Answer - B
In N,N-dimethylaniline the electron -releasing methy1 groups push electrons towards nitrogen and make the lone pair on N more available for protonation However bulky substituents in the ortho (2,6) positions cause steric inhibition of resonance of N lone pair with the ring `-NO_(2)` group is more electron withdrawing relative to -CN group Bulky substituents one the adjacrent 3,5-positions sterically hinder the electron- withdrawing base weakening effect of `NO_(2)` group .