Free Alcohols and Phenols MCQs with Answers
535 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.
Alcohols are classified as primary, secondary or tertiary and studied through their hydrogen bonding, acidity, oxidation and reactions with active metals, acids and halogenating agents. Phenols require separate treatment because the hydroxyl group is attached to an aromatic ring, making their acidity and electrophilic substitution different from ordinary alcohols.
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Read the Alcohols and Phenols notesFree MDCAT chapter notes with key terms535 questions · page 2 of 27
- 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…
Correct answer: Phenol is weakly acidic due to resonance stabilization of phenoxide ion- A. alkane
- B. carboxylic acid
- C. Acetylene
- D. ketone
Explanation: A secondary alcohol has the functional structure R-CHOH-R and oxidation converts it into a ketone, R-CO-R, without changing the carbon…
Correct answer: ketone- A. Acetic acid
- B. Methane
- C. Ethyl alcohol
- D. Methyl alcohol
Explanation: LiAlH4 reduces an aldehyde to a primary alcohol, so acetaldehyde, CH3CHO, becomes ethanol, CH3CH2OH, also called ethyl alcohol.
Correct answer: Ethyl alcohol- A. Primary Alcohol
- B. Secondary Alcohol
- C. Tertiary alcohol
- D. None of These
Explanation: Oxidation of a primary alcohol first gives an aldehyde containing the same number of carbon atoms, for example CH3CH2OH gives CH3CHO.
Correct answer: Primary Alcohol- A. Butanol
- B. Ethylene glycol
- C. Ethanol
- D. Glycerol
Explanation: Soap manufacture by saponification of fats and oils produces glycerol as a by-product, along with the salts of fatty acids that form soap.
Correct answer: Glycerol- A. Primary Alcohol
- B. Secondary Alcohol
- C. Tertiary alcohol
- D. None of These
Explanation: LiAlH4 reduces a ketone's carbonyl group to an -OH group while retaining both carbon groups attached to that carbon, producing a secondary…
Correct answer: Secondary Alcohol- A. More Soluble in water
- B. Insoluble in water
- C. Soluble in water on heating
- D. Insoluble in all solvents
Explanation: Lower molecular-weight alcohols are relatively soluble in water because their polar hydroxyl group forms hydrogen bonds with water, and…
Correct answer: More Soluble in water- A. Conc. HCl & Anhydrous ZnCl2
- B. Dil. HCl & hydrated ZnCl2
- C. Conc. HNO3 & Anhydrous ZnCl2
- D. Conc. HNO3 & Anhydrous MgCl2
Explanation: Lucas reagent is a mixture of concentrated HCl and anhydrous ZnCl2. ZnCl2 acts as a Lewis acid and helps convert the alcohol's -OH group…
Correct answer: Conc. HCl & Anhydrous ZnCl2- A. CH3COOH
- B. CH3CHO
- C. HCOOH
- D. CH3COCH3
Explanation: Methyl alcohol, CH3OH, is a primary alcohol and strong oxidation with acidified K2Cr2O7 carries it through methanal to methanoic acid…
Correct answer: HCOOH- A. Ethene
- B. Diethyl ether
- C. Acetylene
- D. Ethyl hydrogen sulphate
Explanation: Ethanol with concentrated H2SO4 can form ethene by dehydration, diethyl ether at a lower temperature, and ethyl hydrogen sulfate by…
Correct answer: Acetylene- A. 1° alcohol
- B. 2° alcohol
- C. 3° alcohol
- D. 0° alcohol
Explanation: A tertiary alcohol does not undergo ordinary oxidation easily because the carbon bearing the -OH group has no hydrogen that can be removed…
Correct answer: 3° alcohol- A. Aldehyde
- B. Ketone
- C. Carboxylic acid
- D. Ester
Explanation: Oxidation of a secondary alcohol removes hydrogen from the carbon bearing the -OH group and forms a carbonyl group, producing a ketone.
Correct answer: Ketone- A. Bacteria
- B. Virus
- C. Fungi
- D. Algae
Explanation: Algae can act as aquatic solar fuel cells because they use sunlight to produce biomass and energy-rich fuels through photosynthesis.
Correct answer: Algae- A. (CH3)2CHOH
- B. CH3(CH2)OH
- C. CH3CH2OH
- D. (CH3)3COH
Explanation: Lucas reagent reacts fastest with tertiary alcohols because the reaction proceeds through a relatively stable tertiary carbocation, giving…
Correct answer: (CH3)3COH- A. alkyl halides
- B. alkyl amine
- C. alkanes
- D. alkynes
Explanation: Phosphorus halides such as PCl5, PCl3, and PBr3 replace the hydroxyl group of an alcohol with a halogen, producing an alkyl halide.
Correct answer: alkyl halides- A. CH3OH
- B. C3H7OH
- C. CH3 - CH2 - OH
- D. C6H5OH
Explanation: Fermentation of glucose by yeast produces ethanol, represented by CH3CH2OH, along with carbon dioxide: C6H12O6 gives 2C2H5OH + 2CO2.
Correct answer: CH3 - CH2 - OH- A. As a solvent
- B. As an antifreezing agent
- C. As a substitute for petrol
- D. For denaturing of ethyl alcohol
Explanation: Methanol is used as a solvent, an antifreeze, and a denaturant for ethanol, but it is highly toxic and is not commonly used as a…
Correct answer: As a substitute for petrol- A. Cone. HCI and anhydrous SOCl2
- B. Cone. HCI and anhydrous CaCl2
- C. Cone. HCI and anhydrous PCl2
- D. Cone. HCI and anhydrous ZnCl2Education
Explanation: The Lucas test uses concentrated HCl and anhydrous ZnCl2, which converts alcohols into insoluble alkyl chlorides at different rates…
Correct answer: Cone. HCI and anhydrous ZnCl2Education- A. propane
- B. Propanol
- C. Propanone
- D. Propanoic acid
Explanation: Isopropyl alcohol is a secondary alcohol, and oxidation of a secondary alcohol gives a ketone without breaking the carbon skeleton.
Correct answer: Propanone- A. 12% alcohol
- B. 90% alcohol
- C. 95% alcohol
- D. 100% alcohol
Explanation: Rectified spirit is ethanol purified by repeated distillation, but ethanol and water form an azeotrope, so ordinary distillation gives…
Correct answer: 95% alcohol