MolSynapsequestion bank

MolSynapse / Question bank / General Organic Chemistry II: Acids and Bases / Basic strength of amines and heterocycles

JEE Main levelSingle correct optionDifficulty 2 of 3g2069

In aqueous solution $(CH X_{3}) X_{3} N$ is a weaker base than $(CH X_{3}) X_{2} NH$ because

Atrimethylamine has no lone pair on nitrogen
Bmethyl groups are electron-withdrawing by $- I$ effect
Ctrimethylamine has a lower molar mass
Dthe ammonium ion $(CH X_{3}) X_{3} NH X^{+}$ has only one N-H bond for hydrogen bonding with water and the N atom is sterically crowded

Answer: D

Basicity in water depends on both the

+ I

effect and solvation of the conjugate acid.

(CH X_{3}) X_{3} NH X^{+}

has one N-H for H-bonding with water (versus two for

(CH X_{3}) X_{2} NH X_{2} X^{+}

), and steric crowding adds to the effect; these outweigh the extra

+ I

effect.

Practice General Organic Chemistry II: Acids and Bases More on Basic strength of amines and heterocycles

Previous questionNext question

More questions on Basic strength of amines and heterocycles