Q47 / 150 · MHT CET 2026 (16 April Shift 2) · Chemistry
Which of the following molecules is capable of forming Zwitter ion?
- Correct answerA$\text{NH}_2\text{CH}_2\text{COOH}$
- B$\text{CH}_3\text{COOH}$
- C$\text{CH}_3\text{CH}_2\text{NH}_2$
- D$\text{CCl}_3\text{NO}_2$
Solution
A Zwitter ion is a dipolar ion formed by the internal transfer of a proton from an acidic group to a basic group within the same molecule.
Among the given options, $\text{NH}_2\text{CH}_2\text{COOH}$ (glycine) is an amino acid that contains both an acidic carboxyl group ($-\text{COOH}$) and a basic amino group ($-\text{NH}_2$).
In aqueous solution, the $-\text{COOH}$ group donates a proton to the $-\text{NH}_2$ group, forming the Zwitter ion $^{+}\text{NH}_3\text{CH}_2\text{COO}^{-}$.
The other molecules lack either an acidic or a basic group required for this internal proton transfer.
Answer: $\text{NH}_2\text{CH}_2\text{COOH}$
Among the given options, $\text{NH}_2\text{CH}_2\text{COOH}$ (glycine) is an amino acid that contains both an acidic carboxyl group ($-\text{COOH}$) and a basic amino group ($-\text{NH}_2$).
In aqueous solution, the $-\text{COOH}$ group donates a proton to the $-\text{NH}_2$ group, forming the Zwitter ion $^{+}\text{NH}_3\text{CH}_2\text{COO}^{-}$.
The other molecules lack either an acidic or a basic group required for this internal proton transfer.
Answer: $\text{NH}_2\text{CH}_2\text{COOH}$
Hence, the correct answer is option: 'A'.