Question

Amongst the following the strongest base in aqueous medium is _____.

• A. $CH_{3}NH_{2}$
• B. $NCCH_{2}NH_{2}$
• C. $(CH_{3})_{2}NH$
• D. $C_{6}H_{5}NHCH_{3}$

Answer 1

Answer: (C)

$(CH_{3})_{2}NH$

Answer 2

: In aqueous medium $2º$amine $(CH_{3})_{2}NH$ is more basic than $1º$amine $(CH_{3}NH_{2})$. Due to –I effect of $- CN$ group, $NCCH_{2}NH_{2}$ is less basic than $CH_{3}NH_{2}$ and due to delocalisaiton of lone pair of electrons of N atom in benzene ring $C_{6}H_{5}NHCH_{3}$is less basic than $CH_{3}NH_{2}$and more basic than $NC - CH_{2}NH_{2}$.thus the strongest base in aqueous medium is $(CH_{3})_{2}NH$