Arrange the following anilines in decreasing order of basicity 1. C6H5NH2 2. o-CH3C6H4NH2 3. m-CH3C6H4NH2 4. p-CH3C6H4NH2

Question

Arrange the following anilines in decreasing order of basicity 1. C6H5NH2 2. o-CH3C6H4NH2 3. m-CH3C6H4NH2 4. p-CH3C6H4NH2 (A) 4 > 1 > 2 > 3 (B) 4 > 3 > 1 > 2 (C) 1 > 2 > 3 > 4 (D) 4 > 3 > 2 > 1

Tardigrade Admin · Accepted Answer

-CH3 group is inductively electron-donating and base-strengthening from all position. Moreover, if -CH3 is attached to benzene ring (or if R has benzylic H), it is electron-donating by hyper-conjugation from the ortho and para positions. Because of ortho effect, o-substituted aniline become less basic than aniline. Thus, p-CH3C6H4NH2 (hyper-conjugation and induction) > m-CH3C6H4NH2 (induction) > C6H5NH2>o-CH3C6H4NH2 (ortho effect).

Q. Arrange the following anilines in decreasing order of basicity 1. C6​H5​NH2​ 2. o−CH3​C6​H4​NH2​ 3. m−CH3​C6​H4​NH2​ 4. p−CH3​C6​H4​NH2​

4 > 1 > 2 > 3

4 > 3 > 1 > 2

1 > 2 > 3 > 4

4 > 3 > 2 > 1

Q. Arrange the following anilines in decreasing order of basicity

$1.$ $C_{6} H_{5} N H_{2}$

$2.$ $o - C H_{3} C_{6} H_{4} N H_{2}$

$3.$ $m - C H_{3} C_{6} H_{4} N H_{2}$

$4.$ $p - C H_{3} C_{6} H_{4} N H_{2}$