Answer: Salicylaldehyde.
- A Benzoic acid
- B Salicylaldehyde
- C Aniline
- D Benzyl alcohol
Correct answer: B. Salicylaldehyde
Explanation: Phenol reacts with chloroform and alkali in Reimer-Tiemann reaction to form salicylaldehyde.
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.