JEE Main · 2026 · 05 Apr 2026 · Shift 2 · Aldehydes Ketones and Carboxylic Acids

The substrate is propanenitrile, $\mathrm{C}{\mathrm{H}}_3\mathrm{C}{\mathrm{H}}_2\mathrm{C}\equiv \mathrm{N}$. Alkaline hydrolysis followed by acidification (steps i and ii) converts the nitrile to propanoic acid, $\mathrm{C}{\mathrm{H}}_3\mathrm{C}{\mathrm{H}}_2\mathrm{COOH}$. Treatment with chlorine and red phosphorus (step iii) is the Hell--Volhard--Zelinsky reaction, which chlorinates the carbon $\alpha$ to the carboxyl group by way of the acid chloride; aqueous work-up (step iv) hydrolyses the intermediate to the $\alpha$-chloro acid, $\mathrm{C}{\mathrm{H}}_3\mathrm{CHClCOOH}$. The major product P is 2-chloropropanoic acid.