Which set of reagents is used to form an ester from an alcohol and a carboxylic acid under acidic conditions?

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Multiple Choice

Which set of reagents is used to form an ester from an alcohol and a carboxylic acid under acidic conditions?

The key idea is Fischer esterification, where an alcohol and a carboxylic acid form an ester in the presence of a strong acid catalyst. The acid (like sulfuric acid) protonates the carbonyl oxygen, making the carbonyl carbon more electrophilic so the alcohol can attack. After proton transfers, water is produced and leaves; removing water helps drive the equilibrium toward ester formation. So the reagent set that fits this process includes the alcohol, the carboxylic acid, and a catalytic amount of acid. Without the acid catalyst, the condensation proceeds very slowly and isn’t driven to completion, which is why just alcohol and carboxylic acid aren’t enough. An alternative route uses acid chloride and alcohol, which is a different mechanism and doesn’t rely on forming the ester directly from a carboxylic acid under acidic conditions. A base in aqueous solution would deprotonate species and actually hinder ester formation.

The key idea is Fischer esterification, where an alcohol and a carboxylic acid form an ester in the presence of a strong acid catalyst. The acid (like sulfuric acid) protonates the carbonyl oxygen, making the carbonyl carbon more electrophilic so the alcohol can attack. After proton transfers, water is produced and leaves; removing water helps drive the equilibrium toward ester formation. So the reagent set that fits this process includes the alcohol, the carboxylic acid, and a catalytic amount of acid.

Without the acid catalyst, the condensation proceeds very slowly and isn’t driven to completion, which is why just alcohol and carboxylic acid aren’t enough. An alternative route uses acid chloride and alcohol, which is a different mechanism and doesn’t rely on forming the ester directly from a carboxylic acid under acidic conditions. A base in aqueous solution would deprotonate species and actually hinder ester formation.

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