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Alcohols and Phenols MCQs for MDCAT Practice

Chemistry section, Alcohols and Phenols chapter. Up to eight free sample questions, each with the correct answer and a worked explanation. The full chapter opens in the app.

The bank has 848 active questions on this chapter. Your first 500 practice attempts are free, and every attempt includes a worked explanation.

  1. Question 1
    The oxidative cleavage of the given diol produces
    Diagram for this question, with no written description.
    • 2 molecules of ketone.
    • 1 molecule of ketone and 1 molecule of ester.
    • 1 molecule of aldehyde and 1 molecule of ester.
    • 2 molecules of aldehyde. (correct answer)
    Correct answer: D
    Oxidative cleavage of vicinal diols with periodate yields aldehydes or ketones based on the substitution of the carbons bearing the hydroxyl groups.
  2. Question 2
    Why are lower alcohols more soluble in water than higher alcohols?
    • ecause lower alcohols form stronger hydrogen bonds with water due to their smaller size. (correct answer)
    • ecause lower alcohols have higher molecular weight, making them more polar.
    • ecause higher alcohols have stronger hydrogen bonding with water.
    • ecause higher alcohols have longer nonpolar hydrocarbon chains that resist dissolution.
    Correct answer: A
    Lower alcohols are more water-soluble due to increased hydrogen bonding capacity relative to their hydrophobic alkyl chains, a trend that reverses with increasing chain length.
  3. Question 3
    Which is most acidic?
    • H2O (correct answer)
    • C2H5OH
    • C4H9OH
    • CH3-CH2-CH2OH
    Correct answer: A
    Acidity of alcohols and water is determined by the stability of their conjugate bases; electron-donating groups decrease acidity.
  4. Question 4
    Which of the following statements about the acid-base reaction of phenol is true?
    • Phenol acts as a proton acceptor
    • Phenol acts as a proton donor (correct answer)
    • Phenol does not undergo acid-base reactions
    • Phenol reacts with both acids and bases
    Correct answer: B
    Phenol's acidic nature stems from resonance stabilization of its phenoxide ion, making it a weak acid.
  5. Question 5
    Phenol is a ____ liquid.
    • Dense
    • Hard
    • Deliquescent (correct answer)
    • Intermittent
    Correct answer: C
    Phenol's hygroscopic nature means it absorbs atmospheric moisture, making it 'deliquescent'. This property is key to understanding its physical behavior.
  6. Question 6
    Which of following compound is solid at room temperature?
    • Ethanol
    • Phenol (correct answer)
    • Butane
    • Methanol
    Correct answer: B
    Phenol's extensive hydrogen bonding, due to its -OH group attached to an aromatic ring, results in a higher melting point, making it solid at room temperature.
  7. Question 7
    Primary alcohols upon oxidation with acified dichromate gives:
    • Aldehydes (correct answer)
    • Ketones
    • Alkenes
    • Alkynes
    Correct answer: A
    Primary alcohols are oxidized to aldehydes by acidified dichromate. Further oxidation to carboxylic acids requires stronger conditions or excess oxidizing agent.
  8. Question 8
    The temperature required for the dehydration of ethanol into ethene in the presence of H2SO4 is:
    • 130°C
    • 175°C
    • 170°C
    • 180°C (correct answer)
    Correct answer: D
    Dehydration of ethanol to ethene requires concentrated H2SO4 at 180°C, distinguishing it from ether formation at 130°C.

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