Free Alcohols and Phenols MCQs with Answers

• A. their molecules are hydrogen bonded to one another
• B. they are ionic compounds
• C. their covalent bonds are stronger
• D. they have larger molecules

Explanation: The hydroxyl group allows hydrogen bonding between molecules, and a great deal of extra energy is needed to break those bonds before the…

• A. a ketone
• B. an aldehyde
• C. a carboxylic acid
• D. an alkene

Explanation: Distilling removes the aldehyde as soon as it is produced, before it can be oxidised further, whereas heating under reflux keeps it in the…

• A. carries a positive charge
• B. is attached to a halogen
• C. has no hydrogen atom attached to it
• D. is part of a benzene ring

Explanation: Oxidation of an alcohol involves removing the hydroxyl hydrogen together with a hydrogen from the same carbon, and in a tertiary alcohol…

• A. ethane
• B. ethanoic acid
• C. ethoxyethane
• D. ethene

Explanation: At the higher temperature water is eliminated from one molecule to give the alkene, while at about 140 degrees two molecules condense…

• A. sodium ethoxide and hydrogen
• B. sodium ethanoate and water
• C. ethene and sodium hydroxide
• D. no reaction at all

Explanation: The hydroxyl hydrogen is weakly acidic, so sodium displaces it to give an ionic alkoxide and hydrogen gas, though the reaction is far…

• A. an aldehyde
• B. an ester with a fruity smell
• C. an alkene
• D. a soap

Explanation: Esterification joins the acid and the alcohol with the loss of water, giving ethyl ethanoate, and the sulphuric acid acts both as catalyst…

• A. any primary alcohol
• B. methanol
• C. ethanol and other alcohols containing the CH3CH(OH) group
• D. all tertiary alcohols

Explanation: The test needs a methyl group attached to the carbon bearing the hydroxyl, so ethanol and propan-2-ol respond while methanol and…

• A. phenol contains more oxygen
• B. phenol is a solid at room temperature
• C. the hydroxyl group in phenol is attached to an sp3 carbon
• D. the phenoxide ion is stabilised by delocalisation of the negative charge into the benzene ring

Explanation: Losing the hydroxyl hydrogen gives an ion whose negative charge is spread over the aromatic ring rather than concentrated on one oxygen…

• A. a stronger acid than carbonic acid
• B. a weaker acid than carbonic acid but strong enough to react with a strong base
• C. not acidic at all
• D. a base

Explanation: Phenol is acidic enough to be neutralised by a strong alkali, giving sodium phenoxide, but too weak to displace carbon dioxide from a…

• A. bromobenzene
• B. phenyl bromide
• C. 2,4,6-tribromophenol
• D. benzene hexabromide

Explanation: The hydroxyl group is strongly activating and directs substitution to the two and four positions, so all three are brominated at once…

• A. a violet coloured complex
• B. a white precipitate
• C. carbon dioxide gas
• D. no visible change

Explanation: Phenols form a coloured complex with iron three ions, usually violet, and this is a quick confirmatory test for the phenolic hydroxyl…

• A. CH3CH2CH2OH
• B. CH3CH(OH)CH3
• C. (CH3)3COH
• D. CH3OH

Explanation: In propan-2-ol the carbon carrying the hydroxyl group is attached to two other carbons, which is the definition of secondary.

• A. fermentation with yeast
• B. oxidation with acidified dichromate
• C. reduction with hydrogen
• D. direct hydration with steam over a phosphoric acid catalyst

Explanation: Steam and ethene are passed over phosphoric acid at about 300 degrees Celsius and 60 atmospheres, giving a pure product continuously from…

• A. carbon dioxide and water
• B. methanoic acid and methanal, which damage the optic nerve
• C. ethanol
• D. glucose

Explanation: The same enzyme that handles ethanol converts methanol into methanal and then methanoic acid, and these attack the optic nerve and cause…

• A. a monohydric alcohol
• B. a dihydric alcohol
• C. a trihydric alcohol
• D. a phenol

Explanation: Ethylene glycol contains two hydroxyl groups on adjacent carbons, so it is dihydric, while glycerol with three hydroxyls is trihydric and…

• A. hydration of benzene
• B. oxidation of toluene
• C. cumene process, which also yields propanone
• D. fermentation of glucose

Explanation: Benzene is alkylated with propene to give cumene, which is oxidised and then cleaved with acid into phenol and propanone, so two useful…

• A. Sodium metal
• B. Bromine water
• C. Water
• D. A lighted splint

Explanation: Phenol decolourises bromine water immediately and gives a white precipitate of the tribromo compound, whereas ethanol produces no visible…

• A. propanal
• B. propanoic acid
• C. propene
• D. propanone

Explanation: Propan-2-ol is a secondary alcohol, so oxidation removes the single hydrogen on the carbinol carbon and leaves a ketone, which resists…

• A. the hydroxyl group disappears in longer molecules
• B. long chain alcohols are gases
• C. the growing non polar hydrocarbon chain cannot form hydrogen bonds with water and dominates the molecule
• D. longer alcohols react with water

Explanation: Methanol, ethanol and propan-1-ol mix with water in all proportions because the hydroxyl group hydrogen bonds effectively, but as the…

• A. phenols contain no hydroxyl group
• B. the phenolic oxygen donates its lone pair into the ring, making it a poorer nucleophile
• C. phenols are stronger bases than alcohols
• D. esters cannot contain a benzene ring

Explanation: Delocalisation of the oxygen lone pair into the aromatic system, the very effect that makes phenol acidic, leaves that oxygen less…