Answer: Benzene ring.
- A sp<sup>3</sup> carbon
- B sp carbon
- C Benzene ring
- D Carbonyl carbon
Correct answer: C. Benzene ring
Explanation: In phenol, the hydroxyl group is directly attached to a benzene ring.
The phenoxide ion's negative charge spreads into the aromatic ring through resonance, lowering its energy and making phenol give up its proton more easily; an alkoxide ion (from a plain alcohol) has nowhere to delocalise the charge, making alcohols far less acidic.
Concept context
Oxygen-containing organic compounds. Understand the acidic nature of phenols, reactions of alcohols (dehydration, oxidation, esterification), and properties of ethers. Includes industrial applications and named reactions.