Alcohols and Phenols Compared

Alcohols and Phenols Compared MDCAT MCQs with answers

7 past paper MCQs on Alcohols and Phenols Compared, from the Alcohols and Phenols unit of MDCAT Chemistry. The year each question appeared is shown where known; tap “Show answer” for the correct option and a short solution.

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1.Which of the following is correct regarding phenol? (MDCAT 2024)

  1. phenol and water are equally acidic
  2. phenol is less acidic than carboxylic acid
  3. phenol is less acidic than water
  4. phenol is less acidic than ethanol
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Correct answer: (b) phenol is less acidic than carboxylic acid

Phenol is more acidic than water and ethanol because its anion is stabilized by the ring, but weaker than a carboxylic acid.

2.Which of the following best explains why phenol reacts with aqueous NaOH, but alcohols do not? (UHS MDCAT 2025)

  1. Phenol has a lower boiling point than alcohol.
  2. Alcohols contain a strong O-H bond that cannot be broken by weak bases.
  3. Phenol form hydrogen bonding that facilitates ionization.
  4. Phenol is weakly acidic due to resonance stabilization of phenoxide ion.
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Correct answer: (d) Phenol is weakly acidic due to resonance stabilization of phenoxide ion.

The ring delocalizes the charge of the phenoxide ion, so phenol is acidic enough to give a salt with sodium hydroxide.

3.Phenol differs from ethanol because it: (SIBA MDCAT 2025)

  1. Forms stronger hydrogen bonds to its aromatic ring
  2. Is more acidic because of resonance stabilized conjugate base
  3. Readily undergoes nucleophilic substitution at the -OH group
  4. Is completely insoluble in water due to its benzene ring
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Correct answer: (b) Is more acidic because of resonance stabilized conjugate base

The ring spreads the negative charge of the phenoxide ion, which ethanol cannot do, so phenol is the stronger acid.

4.Both alcohols and phenols contain: (SZABMU MDCAT 2023)

  1. – OH group
  2. – COOH group
  3. – CH2 group
  4. – CHO group
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Correct answer: (a) – OH group

Both carry the hydroxyl group; in a phenol it is attached to a benzene ring.

5.Which of the following reactions differentiates alcohol from phenol? (NUMS MDCAT 2023)

  1. Lucas test
  2. Halogenations
  3. Nitration
  4. Iodoform test
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Correct answer: (a) Lucas test

Lucas reagent reacts with alcohols; phenol does not give a halide at all.

6.Which of the following reactions are given by alcohol and phenol both? (PMC MDCAT 2022)

  1. Esterification
  2. Nitrosation
  3. Amide formation
  4. Lucas Reaction
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Correct answer: (a) Esterification

Both the alcohol and the phenol give esters with an acid chloride or anhydride.

7.Lucas test is used for the identification of: (NUMS MDCAT 2022)

  1. Alkyl halides
  2. Alcohols
  3. Alkene
  4. Carboxylic acids
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Correct answer: (b) Alcohols

Lucas reagent tells primary, secondary and tertiary alcohols apart by how fast each turns cloudy.

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