Lesson 3.3.8

3.3.8 Aldehydes and ketones Quiz: AQA Chemistry, Unit 3

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.3.8, Aldehydes and ketones: 20 multiple choice questions for the AQA Chemistry (7405), Unit 3: Organic chemistry, written with Revision Ninja.

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The 20 questions

  1. Which type of reaction is the reduction of an aldehyde by NaBH4?

    • Free-radical substitution
    • Elimination
    • Nucleophilic addition
    • Electrophilic substitution

  2. What is the product when a ketone is reduced by NaBH4 in aqueous solution?

    • An ester
    • A carboxylic acid
    • A secondary alcohol
    • A primary alcohol

  3. What toxic gas is released when potassium cyanide solution is acidified?

    • Sulfur dioxide
    • Hydrogen cyanide
    • Ammonia gas
    • Chlorine gas

  4. Why does nucleophilic addition to an unsymmetrical aldehyde form a racemic mixture?

    • Chiral reactant
    • Free carbon rotation
    • Planar carbonyl group
    • Tetrahedral carbonyl carbon

  5. Which reagent distinguishes aldehydes from ketones by forming a silver mirror?

    • Tollens' reagent
    • Fehling's solution
    • Bromine water
    • Acidified potassium dichromate

  6. Which equation correctly shows the reduction of ethanal using [H] as the reductant?

    • CH3CHO + 2[H] -> CH3COOH
    • CH3CHO + [H] -> CH3CH2OH
    • CH3CHO + 2[H] -> CH3CH2OH
    • CH3CHO + [H] -> CH3COOH

  7. What is the product when propanal reacts with HCN and then forms the hydroxynitrile?

    • 2-hydroxypropanenitrile
    • 2-hydroxybutanenitrile
    • Propan-2-ol
    • Butanoic acid

  8. Why is the product of propanone reacting with KCN optically inactive?

    • Insoluble in water
    • Racemic mixture formed
    • No chiral centre
    • Contains double bonds

  9. What is the role of dilute acid in the reaction of KCN with carbonyls?

    • Protonate alkoxide ion
    • Deprotonate carbonyl carbon
    • Provide nucleophile
    • Oxidise intermediate

  10. What converts the alkoxide intermediate to an alcohol during reduction with aqueous NaBH4?

    • Oxidation by oxygen
    • Deprotonation by hydroxide
    • Hydride ion attack
    • Protonation by water

  11. What organic product is formed when butanone is reduced by NaBH4?

    • Achiral butan-2-ol
    • Chiral butan-2-ol
    • Achiral butan-1-ol
    • Chiral butan-1-ol

  12. What is the equation for the reduction of propanone by [H]?

    • CH3COCH3 + [H] -> CH3CH2CH2OH
    • CH3COCH3 + 2[H] -> CH3CH2COOH
    • CH3COCH3 + 2[H] -> CH3CH(OH)CH3
    • CH3COCH3 + [H] -> CH3COOH

  13. Why can aldehydes be oxidised by Fehling's solution while ketones cannot?

    • Hydroxyl O-H bond
    • Carbonyl C-H bond
    • Carbonyl C=O bond
    • Carbonyl C-C bond

  14. What organic product forms when ethanal is reduced by aqueous NaBH4?

    • Ethene
    • Ethanol
    • Ethanal
    • Ethanoic acid

  15. Which ketone does NOT form a pair of enantiomers after reaction with KCN and dilute acid?

    • Propanone
    • Ethanal
    • Pentan-2-one
    • Butanal

  16. What is the functional group formed when an aldehyde is oxidised?

    • Alkene (C=C)
    • Primary amine (-NH2)
    • Ester (-COO-)
    • Carboxylic acid (-COOH)

  17. Which species acts as the nucleophile in the reaction of KCN with a carbonyl compound?

    • Cyanide ion
    • Water molecule
    • Hydrogen ion
    • Potassium ion

  18. Which compound with formula C4H8O gives a silver mirror with Tollens' reagent?

    • Butanone
    • But-3-en-1-ol
    • Cyclobutanol
    • Butanal

  19. What type of alcohol is formed when a ketone is reduced by NaBH4?

    • Tertiary alcohol
    • Primary alcohol
    • Quaternary alcohol
    • Secondary alcohol

  20. What is the relative molecular mass of the hydroxynitrile formed from ethanal and HCN, CH3CH(OH)CN?

    • 57
    • 71
    • 69
    • 85

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