60 free MCQs on Alcohols, Phenols & Ethers with worked answers and explanations. Oxygen-containing organic compounds. Understand the acidic nature of phenols, reactions of alcohols (dehydration, oxidation, esterification), and properties of ethers. Includes industrial applications and named reactions.
Take the timed Alcohols, Phenols & Ethers chapterwise test →Below are 60 practice questions on Alcohols, Phenols & Ethers, sorted Easy → Hard. Tap “Show answer & explanation” under any question to check yourself. Want the full theory first? Read the Alcohols, Phenols & Ethers notes.
The phenoxide ion's negative charge spreads into the aromatic ring through resonance, lowering its energy and making phenol give up its proton more easily; an alkoxide ion (from a plain alcohol) has nowhere to delocalise the charge, making alcohols far less acidic.
Q1.
Which functional group is present in alcohols?
Answer: B. -OH
Why: Alcohols contain the hydroxyl functional group represented by -OH.
Q2.
What type of alcohol is CH<sub>3</sub>CH<sub>2</sub>OH?
Answer: A. Primary alcohol
Why: Ethanol is a primary alcohol because the carbon carrying OH is attached to only one other carbon.
Q3.
Which alcohol is highly poisonous?
Answer: B. Methanol
Why: Methanol is toxic and can cause blindness or death.
Q4.
Which reagent is used in Lucas test?
Answer: A. ZnCl<sub>2</sub> and HCl
Why: Lucas reagent consists of concentrated HCl and anhydrous ZnCl<sub>2</sub>.
Q5.
Which alcohol reacts fastest in Lucas test?
Answer: C. Tertiary alcohol
Why: Tertiary alcohols react fastest due to stable carbocation formation.
Q6.
Why do alcohols have higher boiling points than alkanes?
Answer: B. Hydrogen bonding
Why: Alcohol molecules form intermolecular hydrogen bonds which increase boiling point.
Q7.
Which alcohol is commonly used in sanitizers?
Answer: B. Ethanol
Why: Ethanol is widely used in hand sanitizers because of its antiseptic properties.
Q8.
What is the common name of propane-1,2,3-triol?
Answer: B. Glycerol
Why: Propane-1,2,3-triol is commonly called glycerol.
Q9.
Phenol differs from alcohol because OH group is attached to:
Answer: C. Benzene ring
Why: In phenol, the hydroxyl group is directly attached to a benzene ring.
Q10.
Denatured alcohol is ethanol mixed with:
Answer: C. Poisonous substances
Why: Denatured alcohol contains poisonous additives to prevent drinking.
Q11.
Which alcohol is used as antifreeze?
Answer: C. Ethylene glycol
Why: Ethylene glycol is widely used as antifreeze in automobile radiators.
Q12.
Which compound contains an ether linkage?
Answer: B. CH<sub>3</sub>OCH<sub>3</sub>
Why: Dimethyl ether contains an oxygen atom linked to two alkyl groups.
Q13.
Which alcohol is produced during fermentation of sugar?
Answer: B. Ethanol
Why: Fermentation of sugars by yeast produces ethanol.
Q14.
What is the IUPAC name of CH<sub>3</sub>OH?
Answer: B. Methanol
Why: CH<sub>3</sub>OH is the simplest alcohol and is called methanol.
Q15.
Which type of alcohol has the OH-bearing carbon attached to three alkyl groups?
Answer: C. Tertiary
Why: Tertiary alcohols have the OH-bearing carbon attached to three alkyl groups.
Q16.
Which compound is aromatic?
Answer: B. Phenol
Why: Phenol contains a benzene ring and is aromatic.
Q17.
Which compound is used as a solvent and was formerly used as an anesthetic?
Answer: B. Diethyl ether
Why: Diethyl ether has been used as a solvent and anesthetic.
Q18.
Which compound gives violet colour with FeCl<sub>3</sub>?
Answer: B. Phenol
Why: Phenol reacts with neutral ferric chloride to give a violet colour.
Q19.
Which alcohol has the formula C<sub>2</sub>H<sub>5</sub>OH?
Answer: B. Ethanol
Why: C<sub>2</sub>H<sub>5</sub>OH is ethanol, a two-carbon alcohol.
Q20.
Which intermolecular force is strongest in alcohols?
Answer: B. Hydrogen bonding
Why: Hydrogen bonding is responsible for many physical properties of alcohols.
Q21.
What is the major product when ethanol is dehydrated at 443 K?
Answer: B. Ethene
Why: Dehydration of ethanol at high temperature forms ethene.
Q22.
Which alcohol on oxidation gives an aldehyde?
Answer: A. Primary alcohol
Why: Primary alcohols oxidise first to aldehydes and then to carboxylic acids.
Q23.
Which alcohol on oxidation gives a ketone?
Answer: C. Secondary alcohol
Why: Secondary alcohols oxidise to ketones.
Q24.
Why is phenol more acidic than ethanol?
Answer: B. Resonance stabilisation of phenoxide ion
Why: Phenoxide ion is resonance stabilised, increasing the acidity of phenol.
Q25.
Which reaction is used to prepare ethers from alkyl halides?
Answer: B. Williamson synthesis
Why: Williamson ether synthesis forms ethers using alkyl halides and alkoxides.
Q26.
Phenol reacts with sodium metal to produce:
Answer: A. Hydrogen gas
Why: Phenol reacts with sodium to release hydrogen gas and form sodium phenoxide.
Q27.
Which reagent converts alcohol into alkene by dehydration?
Answer: B. Concentrated H<sub>2</sub>SO<sub>4</sub>
Why: Concentrated sulfuric acid causes dehydration of alcohols to alkenes.
Q28.
What is formed when phenol reacts with bromine water?
Answer: B. 2,4,6-tribromophenol
Why: Phenol undergoes electrophilic substitution to form 2,4,6-tribromophenol.
Q29.
Which alcohol does not undergo oxidation easily?
Answer: C. Tertiary alcohol
Why: Tertiary alcohols resist oxidation because they lack alpha hydrogen atoms.
Q30.
What is the product formed when ethanol reacts with sodium?
Answer: B. Sodium ethoxide
Why: Ethanol reacts with sodium to form sodium ethoxide and hydrogen gas.
Q31.
Which acid acts as catalyst in esterification?
Answer: C. Sulfuric acid
Why: Concentrated sulfuric acid acts as a catalyst and dehydrating agent in esterification.
Q32.
What is the product when ethanol is oxidised using acidified KMnO<sub>4</sub>?
Answer: B. Acetic acid
Why: Strong oxidation of ethanol by acidified KMnO<sub>4</sub> produces acetic acid.
Q33.
Which ether is formed by Williamson synthesis using sodium ethoxide and methyl bromide?
Answer: C. Ethyl methyl ether
Why: Ethoxide ion attacks methyl bromide to form ethyl methyl ether.
Q34.
Which compound gives a white precipitate with bromine water?
Answer: C. Phenol
Why: Phenol forms 2,4,6-tribromophenol as a white precipitate with bromine water.
Q35.
What happens when ether reacts with excess HI?
Answer: B. Cleavage to alkyl iodides
Why: HI cleaves ethers to form alkyl iodides and alcohols.
Q36.
Which alcohol is produced by hydration of ethene?
Answer: B. Ethanol
Why: Hydration of ethene in presence of acid catalyst produces ethanol.
Q37.
Which compound is least acidic?
Answer: C. Ethanol
Why: Ethanol is less acidic because the ethoxide ion is not resonance stabilised.
Q38.
Which product is formed during intermolecular dehydration of ethanol at 413 K?
Answer: B. Diethyl ether
Why: At lower temperature, intermolecular dehydration of ethanol forms diethyl ether.
Q39.
What colour is produced when phenol reacts with neutral FeCl<sub>3</sub>?
Answer: C. Violet
Why: Phenol gives a violet coloured complex with ferric chloride.
Q40.
Which alcohol forms a ketone on oxidation?
Answer: C. Propan-2-ol
Why: Propan-2-ol is a secondary alcohol and oxidises to acetone.
Q41.
Which product is formed in Kolbe reaction of sodium phenoxide with CO<sub>2</sub>?
Answer: A. Salicylic acid
Why: Kolbe reaction introduces a carboxyl group ortho to the OH group forming salicylic acid.
Q42.
Reimer-Tiemann reaction converts phenol into:
Answer: B. Salicylaldehyde
Why: Phenol reacts with chloroform and alkali in Reimer-Tiemann reaction to form salicylaldehyde.
Q43.
Which intermediate forms during acid-catalysed dehydration of alcohols?
Answer: C. Carbocation
Why: Acid catalysed dehydration proceeds through carbocation formation.
Q44.
Which alcohol undergoes dehydration most easily?
Answer: C. Tertiary alcohol
Why: Tertiary alcohols form stable carbocations and dehydrate more readily.
Q45.
What is formed when ethanol reacts with ethanoic acid in presence of concentrated H<sub>2</sub>SO<sub>4</sub>?
Answer: B. Ethyl ethanoate
Why: Esterification of ethanol with ethanoic acid forms ethyl ethanoate.
Q46.
Which alcohol cannot be oxidised easily?
Answer: C. Tertiary alcohol
Why: Tertiary alcohols lack alpha hydrogen atoms needed for oxidation.
Q47.
What is the major product when tert-butanol undergoes dehydration?
Answer: C. 2-methylpropene
Why: Dehydration of tert-butanol mainly produces 2-methylpropene.
Q48.
Which reagent is used in Clemmensen reduction?
Answer: A. Zn(Hg) with HCl
Why: Clemmensen reduction uses zinc amalgam and hydrochloric acid to reduce carbonyls to CH<sub>2</sub>.
Q49.
Phenol reacts with benzene diazonium chloride to form:
Answer: B. Azo dye
Why: Phenol undergoes azo coupling with diazonium salt to form brightly coloured azo dyes.
Q50.
Which reaction involves rearrangement of vicinal diols?
Answer: C. Pinacol rearrangement
Why: Pinacol rearrangement converts vicinal diols into carbonyl compounds via 1,2-shift.
Q51.
Which product is formed when phenol reacts with NaOH?
Answer: A. Sodium phenoxide
Why: Phenol is acidic enough to react with NaOH forming sodium phenoxide and water.
Q52.
Which reagent converts phenol into picric acid?
Answer: B. Concentrated HNO<sub>3</sub>
Why: Concentrated nitric acid converts phenol into 2,4,6-trinitrophenol (picric acid).
Q53.
What is the product of oxidation of propan-1-ol with PCC?
Answer: C. Propanal
Why: PCC is a mild oxidising agent that converts primary alcohols to aldehydes without further oxidation.
Q54.
Which alcohol gives positive iodoform test?
Answer: B. Ethanol
Why: Ethanol oxidises to acetaldehyde which gives a positive iodoform test.
Q55.
Which compound undergoes Kolbe electrolysis to give ethane?
Answer: A. Sodium acetate
Why: Kolbe electrolysis of sodium acetate produces ethane at the anode.
Q56.
What is the role of concentrated H<sub>2</sub>SO<sub>4</sub> in esterification?
Answer: C. Catalyst and dehydrating agent
Why: Sulfuric acid catalyses esterification and removes water formed, shifting equilibrium forward.
Q57.
Which product is formed when anisole reacts with HI?
Answer: A. Phenol and methyl iodide
Why: HI cleaves anisole at the weaker C-O bond to produce phenol and methyl iodide.
Q58.
Which compound gives violet colour with FeCl<sub>3</sub> due to phenolic OH group?
Answer: C. Phenol
Why: Phenolic compounds form coloured complexes with ferric chloride.
Q59.
Which intermediate is formed during Williamson ether synthesis?
Answer: B. Alkoxide ion
Why: Alkoxide ions act as nucleophiles attacking the alkyl halide in Williamson ether synthesis.
Q60.
Which alcohol gives ketone on oxidation?
Answer: C. Propan-2-ol
Why: Propan-2-ol is a secondary alcohol and oxidises to propanone (acetone).