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 3 of 27
- 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- A. primary alcohol
- B. secondary alcohol
- C. tertiary alcohol
- D. dihydric alcohol
Explanation: A Grignard reagent opens ethylene oxide and adds its organic group to the ring; acid hydrolysis then converts the magnesium alkoxide into…
Correct answer: primary alcohol- A. formaldehyde
- B. ketone
- C. ethylene epoxide
- D. both A & C
Explanation: Formaldehyde reacts with a Grignard reagent to give a primary alcohol after hydrolysis, and ethylene oxide also gives a primary alcohol…
Correct answer: both A & C- A. formaldehyde
- B. acetaldehyde
- C. propanone
- D. carbondioxide
Explanation: Formaldehyde and aldehydes or ketones react with Grignard reagents to form alcohols after hydrolysis, but CO2 gives a magnesium…
Correct answer: carbondioxide- A. primary alcohol
- B. secondary alcohol
- C. tertiary alcohol
- D. dihydric alcohol
Explanation: Ethyl magnesium bromide adds an ethyl group to acetone, converting the carbonyl carbon into a carbon bonded to three carbon groups and an…
Correct answer: tertiary alcohol- A. ketone
- B. Aldehyde
- C. Alkene then - COOH
- D. Ester
Explanation: A primary alcohol is oxidized first to an aldehyde under controlled conditions, while further oxidation can produce a carboxylic acid.
Correct answer: Aldehyde- A. methylated spirit
- B. wood spirit
- C. rectified spirit
- D. absolute alcohol
Explanation: Ethanol containing about 5% water, or approximately 95% ethanol by volume, is called rectified spirit and cannot be completely purified by…
Correct answer: rectified spirit- A. 12% alcohol
- B. 90% alcohol
- C. 95% alcohol
- D. 100% alcohol
Explanation: Rectified spirit is ethanol purified by fractional distillation to about 95% alcohol by volume, with the remaining water forming an…
Correct answer: 95% alcohol- A. a solvent
- B. an anti freezing agent
- C. a substitute for petrol
- D. for denaturing of ethyl alcohol
Explanation: Methanol is widely used as a solvent, antifreeze, and denaturant for ethanol because it makes alcohol unsuitable for drinking.
Correct answer: a substitute for petrol- A. Benzene
- B. Phenol
- C. Cresol
- D. Aniline
Explanation: Phenol is more acidic than benzene, cresol and aniline because its conjugate base, phenoxide, is resonance-stabilised.
Correct answer: Phenol- A. Phenol
- B. P-nitrophenol
- C. O-nitrophenol
- D. M-nitrophenol
Explanation: The nitro group strongly withdraws electron density and stabilises the phenoxide ion formed when nitrophenol loses H+, increasing acidity.
Correct answer: P-nitrophenol- A. Picric acid
- B. o-nitrophenol
- C. 1 3 5 -trinitro benzene
- D. p-nitrophenol
Explanation: Concentrated nitric acid introduces three nitro groups into phenol, producing 2,4,6-trinitrophenol, commonly called picric acid.
Correct answer: Picric acid- A. Alcohol
- B. Acetic acid
- C. Water
- D. Phenol
Explanation: Phenol is a weak acid with Ka approximately 1.3 x 10^-10, because the phenoxide ion formed after losing H+ is stabilised by resonance.
Correct answer: Phenol