Question

Amongst the following, the strongest base in aqueous medium is ______.

विकल्प

• \[\ce{CH3NH2}\]

• \[\ce{NCCH2NH2}\]

• \[\ce{(CH3)2NH}\]

• \[\ce{C6H5NHCH3}\]

Answer 1

Amongst the following, the strongest base in aqueous medium is \[\ce{(CH3)2NH}\].

Explanation:

2° amine is more basic than 1° amine, i.e., \[\ce{(CH3)2NH}\] is more basic than \[\ce{CH3NH2}\]. Due to \[\ce{^-I}\] effect of \[\ce{CN}\] group, \[\ce{NC-CH2NH2}\] is less basic than \[\ce{CH3NH2}\]. Further \[\ce{C6H5NHCH3}\] is less basic than both \[\ce{CH3NH2}\] and \[\ce{(CH3)2NH}\] due to delocalization of lone pair of electrons present on the nitrogen atom into benzene ring. Hence, the decreasing order of amines is:

\[\ce{(CH3)2NH > CH3NH2 > C6H5NHCH3 > NC – CH2NH2}\]