Correct Answer - A
It is known that `pK_b=logkk_b`
Thus, larger the value of `k_b`, smaller is the value of `pK_b` and hence stronger is the base. The order of basec strength of amines is as follows
`(CH_3)_2overset(..)NHgtCH_3overset(..)(N)H_2(CH_3)_3overset(..)(N)gtC_6H_5overset(..)(N)H_2`
The basic strength of amines depends on the inductive effect as well as steric hindrance of alkyl groups. Hence `(CH_2)_2`
`overset(..)(N)H` [secondary amine] possess the smallest value of `pK_b`
