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

#### 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

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