Free Phenols MCQs with Answers

• 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. 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. 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…

• 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…

• 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.

• 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.

• 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.

• 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.

• A. cyclohexane
• B. n - hexane
• C. 1 - hexanol
• D. cyclohexanol

Explanation: Hydrogenation saturates both the aromatic ring and the phenolic system under catalytic conditions with nickel and heat, producing…

• A. vegetable oil
• B. coaltar
• C. wood
• D. none of these

Explanation: Phenol was first isolated by Runge from coal tar, a complex mixture obtained during the destructive distillation of coal.

• A. Benzene
• B. Benzoic acid
• C. Phenoxide
• D. Cyclohexane

Explanation: Zinc removes the oxygen-containing hydroxyl group from phenol during heating, reducing phenol to benzene: C6H5OH + Zn produces C6H6 + ZnO.

• A. C2H2OH
• B. H2CO3
• C. C6H5OH
• D. H3PO3

Explanation: Carbolic acid is the traditional name for phenol, C6H5OH, because it was historically obtained from coal tar.

• A. monocarboxylc acid
• B. dicarboxylic acid
• C. aromatic carboxylic acid
• D. none of these

Explanation: Picric acid is 2,4,6-trinitrophenol, so it contains a phenolic -OH group and nitro groups, but no carboxyl group.

• A. phthalic acid
• B. carbolic acid
• C. Maleic acid
• D. Succinic acid

Explanation: Carbolic acid is the common name of phenol, C6H5OH, which has a hydroxyl group directly attached to benzene rather than a -COOH group.

• A. phenol is unsaturated
• B. 2-bromophenol is insoluble in water
• C. a hydroxy group makes the benzene ring more susceptible to electrophilic attack
• D. acid-base reaction

Explanation: The hydroxy group donates electron density into the benzene ring by resonance, activating the ring and directing electrophilic…

• A. Slower rate
• B. Faster rate
• C. Equal rate
• D. Moderate rate

Explanation: Nitration of phenol occurs at a faster rate than benzene due to the presence of the hydroxyl (-OH) group in phenol.