Which functional groups react together in a Fischer esterification reaction?

• A. An $\mathrm{aldehyde}$ and an $\mathrm{amine}$
• B. A $\mathrm{ketone}$ and a $\mathrm{thiol}$
• C. An $\mathrm{alkene}$ and a $\mathrm{halide}$
• D. A $\mathrm{carboxylic acid}$ and an $\mathrm{alcohol}$

Answer: (D)

Verified step by step guidance

1. Identify the key functional groups involved in a Fischer esterification reaction. This reaction typically involves the formation of an ester from two specific types of functional groups.
2. Recall that a Fischer esterification is an acid-catalyzed reaction where a carboxylic acid reacts with an alcohol to form an ester and water.
3. Understand the mechanism: the carboxylic acid's carbonyl carbon is electrophilic and is attacked by the nucleophilic oxygen of the alcohol, leading to the formation of a tetrahedral intermediate.
4. Recognize that under acidic conditions, proton transfers facilitate the departure of water, resulting in the formation of the ester functional group.
5. Conclude that the functional groups reacting together in a Fischer esterification are a carboxylic acid and an alcohol.