Answer: B. Butanol is \(\text{CH}_3\text{CH}_2\text{CH}_2\text{CH}_2\text{OH}\) — a four-carbon primary alcohol. Acidified \(\text{KMnO}_4\) oxidises primary alcohols all the way to carboxylic acids.
The –CH₂OH group at the end of butanol is oxidised to –COOH (–\(\text{CO}_2\text{H}\)). The four-carbon backbone is preserved.
Product: \(\text{CH}_3\text{CH}_2\text{CH}_2\text{CO}_2\text{H}\) (butanoic acid) → option B.
A has only three carbons (propanoic acid).
C is an ester, not a carboxylic acid.
D has five carbons, one too many.
Every O Level Pure Chemistry TYS MCQ solution video, plus full Sec 3 / Sec 4 topic recordings.
Find out more