Question

Introduction of a methyl group in ammonia markedly increases the basic strength of ammonia in aq. solution, introduction of the second methyl group increases only marginally the basic strength of methyl amine in water. This is due to.

• A. Different type of hybridisation in the two amines
• B. Protonated dimethyl amine is more solvated than methyl amine
• C. Protonated dimethyl amine is more solvated than the protonated methyl amine
• D. Protonated dimethyl amine is less stable than the protonated methyl amine

Answer 1

The correct option is D

Protonated dimethyl amine is less stable than the protonated methyl amine

The basic character of an amine in water is determined by (i) electron availability on the N atom and (ii) the extent of stabilization of the cation (protonated amine) due to solvation by hydrogen bonding.