Q. In aqueous solutions, the basic strength of amines decreases in the order
A) $CH_{3}NH_{2} > \left( CH_{3} \right)_{2}NH_{2} > \left( CH_{3} \right)_{3}N$
B) $\left( CH_{3} \right)_{2}NH > \left( CH_{3} \right)_{3}N > CH_{3}NH_{2}$
C) $\left( CH_{3} \right)_{3}N > \left( CH_{3} \right)_{2}NH > CH_{3}NH_{2}$
D) $\left( CH_{3} \right)_{2}NH_{2} > CH_{3}NH_{2} > \left( CH_{3} \right)_{3}N$
Explanation
(d)
Basicity of amines depends upon the availability of lone pair of electrons of nitrogen for donation. Electron releasing group increases the electron density over nitrogen, thus increases the basic character. 3${^\circ}$ methyl amine although contains three electron realeasing groups but is least basic because of steric hindrance. Hence, the order of basic character is
$\left( CH_{3} \right)_{2}NH > CH_{3}NH_{2} > \left( CH_{3} \right)_{3}N$
Reviewed by Dr. Abubacker
Physics Educator & NEET/JEE Specialist
Ph.D. in Physics with 19+ years of teaching experience.