Question

Which of the following amines is most basic in nature in aqueous phase?

Options

• Methylamine

• Trimethylamine

• Dimethylamine

• Ammonia

Answer 1

Dimethylamine

Explanation:

In the aqueous phase, dimethylamine is the most basic. Because it is a secondary amine, it is more basic. Due to additional repulsion from the electrons in each C-N bond, the lone pair of electrons on the nitrogen atom are further away from the nucleus at a higher energy level, making the nitrogen atom more capable of donating a pair of electrons. As more OH^- ions are generated when a nitrogen atom absorbs a proton, dimethylamine is a strong base in solution (aqueous phase), leading the solution to become more alkaline as the pH rises.

\[\ce{CH3NHCH3 + H2O -> CH3NH2CH3 + OH-}\]