Given below are two statements: one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A): $$\alpha$$-halocarboxylic acid on reaction with dil. $$NH_3$$ gives good yield of $$\alpha$$-amino carboxylic acid whereas the yield of amines is very low when prepared from alkyl halides.
Reason (R): Amino acids exist in zwitter ion form in aqueous medium.
In the light of the above statements, choose the correct answer from the options given below :

We need to evaluate the Assertion and Reason about the preparation of amino acids from halocarboxylic acids versus amines from alkyl halides.

Analysis of Assertion (A):

"$$\alpha$$-halocarboxylic acid on reaction with dilute $$NH_3$$ gives good yield of $$\alpha$$-amino carboxylic acid whereas the yield of amines is very low when prepared from alkyl halides."

This is CORRECT. When alkyl halides react with $$NH_3$$ (Hoffmann's ammonolysis), the primary amine formed can further react with more alkyl halide to give secondary and tertiary amines, and even quaternary ammonium salts. This leads to a mixture of products and a poor yield of any single amine. However, when $$\alpha$$-halocarboxylic acids react with $$NH_3$$, the $$\alpha$$-amino acid product exists as a zwitterion in aqueous solution, which prevents further reaction with the alkyl halide. This gives a good yield of the amino acid.

Analysis of Reason (R):

"Amino acids exist in zwitter ion form in aqueous medium."

This is CORRECT. Amino acids contain both an amino group ($$-NH_2$$) and a carboxylic acid group ($$-COOH$$). In aqueous solution, the proton transfers from the $$-COOH$$ to the $$-NH_2$$ group, forming a zwitterion: $$^+H_3N-CHR-COO^-$$. This internal salt form is very stable and has no free $$-NH_2$$ group, which is exactly why it cannot react further with alkyl halides.

Relationship between A and R:

The Reason (R) correctly explains the Assertion (A). The formation of the zwitterion is the direct cause of why $$\alpha$$-amino acids are obtained in good yield - the zwitterion form prevents further nucleophilic substitution reactions.

The correct answer is Option (1): Both (A) and (R) are correct and (R) is the correct explanation of (A).