CBSE (Science) Class 12CBSE
Share
Notifications

View all notifications

Arrange the following in increasing order of their basic strength CH3NH2, (CH3)2NH, (CH3)3N, C6H5NH2, C6H5CH2NH2 - CBSE (Science) Class 12 - Chemistry

Login
Create free account


      Forgot password?

Question

Arrange the following in increasing order of their basic strength

CH3NH2, (CH3)2NH, (CH3)3N, C6H5NH2, C6H5CH2NH2.

 

Solution

Considering the inductive effect and the steric hindrance of alkyl groups, CH3NH2, (CH3)2NH, and (CH3)3N can be arranged in the increasing order of their basic strengths as:

`(CH_3)_3N< CH_3NH_2 < (CH_3)_2NH`

In C6H5NH2, N is directly attached to the benzene ring. Thus, the lone pair of electrons on the N−atom is delocalized over the benzene ring. In C6H5CH2NH2, N is not directly attached to the benzene ring. Thus, its lone pair is not delocalized over the benzene ring. Therefore, the electrons on the N atom are more easily available for protonation in C6H5CH2NH2 than in C6H5NH2 i.e., C6H5CHNH2 is more basic than C6H5NH2.

Again, due to the −I effect of C6H5 group, the electron density on the N−atom in C6H5CH2NH2 is lower than that on the N−atom in (CH3)3N. Therefore, (CH3)3N is more basic than C6H5CH2NH2. Thus, the given compounds can be arranged in the increasing order of their basic strengths as follows

`C_6H_5NH_2<C_6H_5CH_2NH_2<(CH_3)_3N<CH_3NH_2<(CH_3)_2NH`

  Is there an error in this question or solution?

APPEARS IN

Solution Arrange the following in increasing order of their basic strength CH3NH2, (CH3)2NH, (CH3)3N, C6H5NH2, C6H5CH2NH2 Concept: Physical Properties of Amines.
S
View in app×