See image — Aldehydes Ketones and Carboxylic Acids Chemistry Question

💡 Solution & Explanation

Concept: Transesterification is the process of exchanging the alkoxy group of an ester with another alcohol, producing a new ester and releasing the original alcohol. Step 1 – Identify the reactants: The left-hand side shows methyl methacrylate (CH2=C(CH3)-C(=O)-OCH3), which is an ester (methyl ester), reacting with n-butanol (a higher alcohol) in the presence of concentrated HCl as an acid catalyst. Step 2 – Identify the products: The right-hand side shows butyl methacrylate (CH2=C(CH3)-C(=O)-O-C4H9) and methanol (MeOH). The methoxy group (-OCH3) of the original ester has been replaced by the butoxy group (-OC4H9) from the butanol, and methanol is released as a byproduct. Step 3 – Classify the reaction: - Esterification (a): Requires a carboxylic acid + alcohol → ester + water. Here, no carboxylic acid is involved; an ester reacts with an alcohol. So (a) is incorrect. - Saponification (b): Base-catalyzed hydrolysis of an ester to give a carboxylate salt and alcohol. No base or water involved here. So (b) is incorrect. - Hydrolysis (c): Cleavage of the ester bond using water. No water is a reactant here. So (c) is incorrect. - Transesterification (d): An ester reacts with an alcohol (acid- or base-catalyzed) to exchange the alkoxy group, forming a new ester and releasing the original alcohol. This exactly matches the reaction shown: methyl methacrylate + butanol → butyl methacrylate + methanol under acid (HCl) catalysis. Therefore, the correct answer is D.