Q78 / 240 · KCET 2026 · Chemistry
Glycerol is a trihydric alcohol. It contains ____.
- AOne primary, one secondary and one tertiary alcoholic groups
- Correct answerBTwo primary and one secondary alcoholic groups
- CTwo secondary and one primary alcoholic groups
- DOne primary and two tertiary alcoholic groups
Solution
The chemical formula of glycerol is $CH_2(OH)-CH(OH)-CH_2(OH)$.
The two terminal $-OH$ groups are attached to primary carbon atoms ($-CH_2-$), making them primary alcoholic groups.
The middle $-OH$ group is attached to a secondary carbon atom ($-CH-$), making it a secondary alcoholic group.
Therefore, glycerol contains two primary and one secondary alcoholic groups.
Answer: Two primary and one secondary alcoholic groups
The two terminal $-OH$ groups are attached to primary carbon atoms ($-CH_2-$), making them primary alcoholic groups.
The middle $-OH$ group is attached to a secondary carbon atom ($-CH-$), making it a secondary alcoholic group.
Therefore, glycerol contains two primary and one secondary alcoholic groups.
Answer: Two primary and one secondary alcoholic groups
Hence, the correct answer is option: 'B'.