Free Alcohols and Phenols MCQs with Answers
21 Alcohols and Phenols MCQs from Chemistry, each with the correct answer and a written explanation of why it is correct. Free and unlimited, with no account needed.
21 questions · page 3 of 3
21. Which of the following best explains why phenol reacts with aqueous NaOH, but alcohols do not?
- A. Phenol has a lower boiling point than alcohol
- B. Alcohols contain a strong O-H bond that cannot be broken by weak bases
- C. Phenol form hydrogen bonding that facilitates ionization
- D. Phenol is weakly acidic due to resonance stabilization of phenoxide ion
Explanation: Losing the hydroxyl hydrogen gives phenol an ion whose negative charge is delocalised into the benzene ring, so the phenoxide ion is far more stable than an alkoxide and the acid dissociates readily enough to be neutralised by sodium hydroxide. An alkoxide has no such delocalisation, so ethanol is not acidic enough to react. Both compounds hydrogen bond, so that cannot be the deciding factor.
Correct answer: Phenol is weakly acidic due to resonance stabilization of phenoxide ion