Question

Amongst the following the strongest base in aqueous medium is:

(a) CH₃NH₂
(b) NC—CH₂NH₂
(c) (CH₃)₂NH
(d) C₆H₅NH—CH₃

Answer 1

(c) (CH₃)₂NH

2° amines are more basic than 1° amines, i. e., (CH₃)₂NH is more basic than CH₃NH₂. Due to -I effect of CN group NC—CH₂NH₂ is less basic than even CH₃NH₂. C₆H₅NHCH₃ is less basic than both C₆H₅NH₂ and (CH₃)₂NH due to delocalisation of lone pair of electrons on the N atom into the benzene ring.