Concept:Hydrolysis of a nitrile yields a carboxylic acid with the
exact same number of carbon atoms.
Formula:$$ \text{CH}_3\text{C}\equiv\text{N} + 2\text{H}_2\text{O} \xrightarrow{\text{H}^+} \text{CH}_3\text{COOH} + \text{NH}_4^+ $$
Solution:- Acetic acid (\( \text{CH}_3\text{COOH} \)) contains exactly 2 carbon atoms.
- To prepare it via hydrolysis, we must start with a 2-carbon nitrile.
- Methyl cyanide (\( \text{CH}_3\text{CN} \)), also known as ethanenitrile, contains 2 carbon atoms.
- Hydrolyzing the \( -\text{CN} \) group converts it into the \( -\text{COOH} \) group of acetic acid.
Why other options are incorrect:Ethanal and ethanol require oxidation, not hydrolysis, to become acetic acid. Methanoic acid is already an acid and has only 1 carbon.
Quality & Fidelity Assurance:
Every question on BeambePrep is rigorously curated against the official PMDC syllabus with zero filler, zero out-of-syllabus content, and zero typos. When an authentic past paper originally contained a historical mistake or ambiguity from the examining board (such as UHS or NUMS), BeambePrep faithfully reflects the original paper while detailing the nuance and scientific consensus in the autopsy above.