Chemistry - Biomolecules Question with Solution | TestHub
Amino acids contain as —NH2 as well as —COOH group. They exist as zwitter ions.
Which explain their several characteristic properties, like decomposition on heating, solubility in water, larger dipole moment. Thus in solution, amino acids may exist as dipolar ion (neutral pH), cationic (In strongly acidic solution), or anionic (in strongly basic solution).
Amino acids undergo usual reaction of the —COOH group as well as —NH2 group
Base treatment of an amino acid usually result in the conversion of the acid to a derivative via the amino carboxylate salt. The above procedure -
Options:
Answer:
Solution:
Question Explanation:
The question asks how base treatment of an amino acid (forming an amino carboxylate salt) affects the reactivity of the amino group.
Concept :
This question is based on Acid-base behaviour of amino acids, Nucleophilicity, Salt formation.
Solution:
On base treatment, the -COOH group of an amino acid is converted to , forming an amino carboxylate salt.
This suppresses internal proton transfer to the –NH2 group, keeping it in the free, unprotonated ( NH2 ) form.
A free –NH2 group has a lone pair available for attack, hence it is more nucleophilic. Therefore, reactions where the amino group acts as a nucleophile (e.g., acylation) are facilitated and rate of nucleophilic reactions increases.
Statement in option (c) is correct.
