Free Alcohols MCQs with Answers
154 Alcohols 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 contain a hydroxyl group attached to a saturated carbon atom and are classified as primary, secondary or tertiary. Their nomenclature, hydrogen bonding, acidity, oxidation, dehydration, reaction with sodium and conversion to haloalkanes are covered, along with the distinction between alcohols and phenols, where the hydroxyl group is attached directly to an aromatic ring.
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- 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- A. ethanol
- B. ethylene glaycol
- C. glycerol
- D. methanol
Explanation: Boiling point rises when stronger intermolecular hydrogen bonding must be overcome.
Correct answer: glycerol- A. Iodoform test
- B. Lucas test
- C. Benedicts test
- D. Tollens test
Explanation: Ethanol gives the iodoform test because it is oxidised to ethanal, which contains the required CH3CO group, and produces yellow iodoform…
Correct answer: Iodoform test- A. Ca(OH)2
- B. CaCO3
- C. CaCl2
- D. CaO
Explanation: Rectified spirit still contains water, and quicklime, CaO, removes it by reacting to form calcium hydroxide: CaO + H2O produces Ca(OH)2.
Correct answer: CaO- A. water gas
- B. destructive distillation of wood
- C. methane
- D. all
Explanation: Methanol is obtained from the destructive distillation of wood and industrially from water gas after catalytic conversion of carbon…
Correct answer: all- A. Hydrogenation
- B. Hydration
- C. Oxidation
- D. Fermentation
Explanation: Ethanol becomes ethanoic acid when it is oxidised, usually with acidified potassium dichromate or potassium permanganate: the primary…
Correct answer: Oxidation- A. Oxygen
- B. Hydrogen
- C. Nascent oxygen[O]
- D. Nascent hydrogen[H]
Explanation: In acidic solution, dichromate acts as an oxidising agent and is often represented in school chemistry as generating nascent oxygen, [O]…
Correct answer: Nascent oxygen[O]- A. Diastase-maltase-zymase
- B. Zymase-maltase-diastase
- C. Maltase-diastase-zymase
- D. Diastase-zymase-maltase
Explanation: Diastase first hydrolyses starch to maltose, maltase converts maltose to glucose, and zymase ferments glucose to ethanol and carbon…
Correct answer: Diastase-maltase-zymase- A. C6H5OH
- B. C6H5CH(OH)2
- C. C6H5CH2OH
- D. C6H5COOH
Explanation: Benzyl alcohol is formed when the hydroxyl group is attached to the carbon next to a benzene ring, giving C6H5CH2OH.
Correct answer: C6H5CH2OH