Concept:The nomenclature of functional groups defines their specific atomic arrangements. An "alkoxy" group is \( \text{-OR} \), and a "carbonyl" group is \( \text{-C=O} \).
Solution:- Combining a carbonyl (\( \text{-C=O} \)) and an alkoxy (\( \text{-OR} \)) group on the same carbon yields the structure \( \text{-COOR} \).
- The \( \text{-COOR} \) linkage is the defining functional group of an ester.
- Note: The source book's answer key table incorrectly listed A, but the book's own explanatory notes and standard chemical definitions confirm D is the correct answer.
Why other options are incorrect:Ethers (A) contain only the alkoxy group without the carbonyl. Aldehydes (B) contain a carbonyl bonded to hydrogen. Carboxylic acids (C) contain a carbonyl bonded to a hydroxyl group (\( \text{-OH} \)), not an alkoxy group.
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