Q16 / 150 · MHT CET 2026 (19 April Shift 1) · Chemistry
Which from the following hydroxy compounds contain only one $-\text{OH}$ group in a molecule?
- Correct answerACrotonyl alcohol
- BEthylene glycol
- CPyrogallol
- DHydroquinone
Solution
Crotonyl alcohol (2-buten-1-ol) has the structure $\text{CH}_3-\text{CH}=\text{CH}-\text{CH}_2\text{OH}$, which contains only one $-\text{OH}$ group.
Ethylene glycol (ethane-1,2-diol) has the structure $\text{HO}-\text{CH}_2-\text{CH}_2-\text{OH}$, which contains two $-\text{OH}$ groups.
Pyrogallol (benzene-1,2,3-triol) contains three $-\text{OH}$ groups attached to a benzene ring.
Hydroquinone (benzene-1,4-diol) contains two $-\text{OH}$ groups attached to a benzene ring.
Therefore, crotonyl alcohol is the only compound among the given options that contains a single $-\text{OH}$ group.
Ethylene glycol (ethane-1,2-diol) has the structure $\text{HO}-\text{CH}_2-\text{CH}_2-\text{OH}$, which contains two $-\text{OH}$ groups.
Pyrogallol (benzene-1,2,3-triol) contains three $-\text{OH}$ groups attached to a benzene ring.
Hydroquinone (benzene-1,4-diol) contains two $-\text{OH}$ groups attached to a benzene ring.
Therefore, crotonyl alcohol is the only compound among the given options that contains a single $-\text{OH}$ group.
Hence, the correct answer is option: 'A'.