Question

Which among the following formulae represents glycollic acid?

• A. $\mathrm{CH_3-CH(OH)-COOH}$
• B. $\mathrm{HOOC-CH_2-CH_2-CH(NH_2)-COOH}$
• C. $\mathrm{HOOC-CH_2-CH(NH_2)-COOH}$
• D. $\mathrm{HO-CH_2-COOH}$

Hint:

Glycollic acid is the simplest hydroxy acid and contains only two carbon atoms.

Answer 1

The Correct Option is D

Step 1: Understanding glycollic acid.
Glycollic acid, also known as hydroxyacetic acid, is the simplest $\alpha$-hydroxy acid. It contains one hydroxyl group and one carboxyl group.

Step 2: Structural requirement.
The molecular formula of glycollic acid is $\mathrm{HO-CH_2-COOH}$, where a hydroxyl group is attached to the carbon adjacent to the carboxyl group.

Step 3: Analysis of options.
Option (A) represents lactic acid. Options (B) and (C) represent amino acids. Only option (D) correctly represents glycollic acid.

Step 4: Conclusion.
Hence, the correct answer is (D) $\mathrm{HO-CH_2-COOH$}.