JEE Main · 2019 · 10 Jan 2019 · Shift 1 · Aldehydes Ketones and Carboxylic Acids

Base-promoted ester hydrolysis proceeds through hydroxide attack on the carbonyl carbon, so anything making that carbon more electron-poor speeds it up. A ring nitro group withdraws electron density strongly and accelerates the attack most, chlorine does so moderately, an unsubstituted ring is intermediate, and an electron-donating methoxy group pushes density in and slows it most. Ranking by how electron-hungry the carbonyl is left gives the ease of hydrolysis as $\text{III}>\text{II}>\text{I}>\text{IV}$.