Phenol reacts with sodium hydroxide solution but not with sodium carbonate solution, which shows that phenol is

  • A. a stronger acid than carbonic acid
  • B. a weaker acid than carbonic acid but strong enough to react with a strong base
  • C. not acidic at all
  • D. a base

Explanation

Phenol is acidic enough to be neutralised by a strong alkali, giving sodium phenoxide, but too weak to displace carbon dioxide from a carbonate, which a carboxylic acid can do. This pair of tests therefore distinguishes a phenol from a carboxylic acid in the laboratory. Ethanol reacts with neither reagent, so the three classes can be told apart in turn.

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