JEE Main 2023 — Biomolecules Question with Solution

The reaction of $\alpha$-halocarboxylic acid with dilute ammonia is known as the haloform reaction. In this reaction, the halogen atom of $\alpha$-halocarboxylic acid is replaced by an amino group to form $\alpha$-amino carboxylic acid. The yield of $\alpha$-amino carboxylic acid is good because the amino group is a better nucleophile than the halogen atom, and it attacks the carbonyl carbon of the carboxylic acid to form an intermediate, which is then hydrolyzed to form the product. On the other hand, when alkyl halides are reacted with ammonia, the yield of amines is very low because alkyl halides are less reactive than $\alpha$-halocarboxylic acids.

The reason (R) is also true. Amino acids exist in the zwitterion form in an aqueous medium. In this form, the amino group has a positive charge, and the carboxyl group has a negative charge. The zwitter ion form is stabilized by the interaction between the opposite charges, which is known as an electrostatic interaction. This interaction makes the zwitterion form more stable than the neutral form.