Which of the following best describes a benzylic carbon in organic molecules?

• A. A carbon atom that is part of the $\mathrm{benzene}$ ring
• B. A carbon atom in a $\mathrm{carboxylic} \mathrm{acid}$ group
• C. A carbon atom attached to two $O$ atoms
• D. A carbon atom directly attached to a $\mathrm{benzene}$ ring

Answer: (D)

Verified step by step guidance

1. Understand the structure of a benzene ring: it is a six-membered aromatic ring with alternating double bonds, represented as C6H6.
2. Define what a benzylic carbon is: it is a carbon atom that is directly attached to the benzene ring but is not part of the ring itself.
3. Distinguish the benzylic carbon from carbons that are part of functional groups such as carboxylic acids or carbons bonded to two oxygen atoms, which are unrelated to the benzylic position.
4. Recognize that the benzylic position is important because the benzylic carbon often exhibits unique reactivity due to resonance stabilization of intermediates formed during reactions.
5. Conclude that the best description of a benzylic carbon is a carbon atom directly attached to a benzene ring, but not part of the ring itself.