The descending order of basicity of the following amines is : Choose the correct answer from the options given below :
- E > A > D > C > B
- E > D > A > B > C
- E > D > B > A > C
- B > E > D > A > C
Answer
(3) E > D > B > A > C
Solution
Aliphatic amines are more basic than aromatic amines because in aryl amines the lone pair of N is delocalised over the ring.
(CH3)2NH (E) > CH3NH2 (D) (+I effect of two methyl groups; in water, pKb 3.27 and 3.38)
Among the anilines:
B: –OMe at the para position donates electrons by +R effect more basic than aniline (pKb 8.70)
A: aniline (pKb 9.38)
C: -NO2 at the para position withdraws electrons by –R and –I effects least basic (pKb 13.0)
E > D > B > A > C
Answer: (3)