ASChemistryCambridge (CIE)Exam Questions17. Carbonyl CompoundsAldehydes & Ketones

Aldehydes & Ketones (Cambridge (CIE) AS Chemistry): Exam Questions

Exam code: 9701

2 hours29 questions

Select a download format for Aldehydes & Ketones

Scroll for more

Select an answer set to view for
Aldehydes & Ketones

Easy
Medium
Hard
1
1 mark

What is formed when butanone is warmed with a solution of NaBH4?

  • Butan-1-ol

  • Butan-2-ol

  • Butanal

  • Butane

Choose your answer

2
1 mark

In 1903, Arthur Lapworth investigated the reaction of hydrogen cyanide with propanone.

What is the name of this type of mechanism?

  • Electrophilic addition

  • Electrophilic substitution

  • Nucleophilic addition

  • Nucleophilic substitution

Choose your answer

3
1 mark

Which carbonyl compound(s) react with both LiAlH4 and Tollens’ reagent?

  • Aldehydes only

  • Both aldehydes and ketones

  • Ketones only

  • Neither aldehydes nor ketones

Choose your answer

4
1 mark

An aqueous methanolic solution of NaBH4 acts as a reducing agent when added to propanal, CH3CH2CHO.

What is the first step of this mechanism?

  • Attack of an H– ion at the carbon atom of the carbonyl group.

  • Attack of an H– ion at the oxygen atom of the carbonyl group.

  • Attack of an H+ ion at the carbon atom of the carbonyl group.

  • Attack of an H+ ion at the oxygen atom of the carbonyl group.

Choose your answer

5
1 mark

The characteristic smell of burnt sugar is partly caused by the following compound.

Structure of a compound containing both an aldehyde and a ketone functional group, contributing to the smell of burnt sugar

Which reagent will react with both functional groups?

  • Acidified potassium dichromate (VI)

  • Fehling’s solution

  • Hydrogen cyanide

  • Sodium hydroxide

Choose your answer

6
1 mark

In which reaction is the organic compound oxidised?

  • CH3CH2CH2OH + concentrated H3PO4

  • CH3CH2CHO + Tollens’ reagent

  • CH3CH2CN + dilute H2SO4

  • CH3COCH2CH3 + 2,4-dinitrophenylhydrazine reagent

Choose your answer

7
1 mark

Ethanal, CH3CHO, is reduced using NaBH4 in aqueous ethanol.

What is the first step of this mechanism?

  • The carbon atom of the carbonyl group is attacked by an H– ion

  • The carbon atom of the carbonyl group is attacked by an H+ ion

  • The oxygen atom of the carbonyl group is attacked by an H– ion

  • The oxygen atom of the carbonyl group is attacked by an H+ ion

Choose your answer

8
1 mark

The orange colour of carrots is due to the presence of β-carotene, the structure of which is shown in the diagram below.

Structure of β-carotene showing a long conjugated carbon chain with multiple C=C double bonds and two six-membered rings with methyl substituents at each end

Excess hot concentrated acidified potassium manganate(VII) will oxidise β-carotene.

When an individual molecule of β-carotene is oxidised in this way there are multiple possible products.

How many of these product molecules contain a ketone functional group?

  • 3

  • 6

  • 9

  • 12

Choose your answer

9
1 mark

Hex-3-enal is used as a flavouring agent.

CH3CH2CH=CHCH2CHO

Which row correctly shows the product formed when hex-3-enal is treated with the given reducing agent?

Product

Reducing agent

A

CH3(CH2)4CH3

H2 + Ni

B

CH3(CH2)4CH2OH

NaBH4

C

CH3(CH2)4CHO

H2 + Ni

D

CH3(CH2)4CHO

NaBH4

    Choose your answer

    1
    1 mark

    When alkaline I2 solution is added to butanone, a yellow precipitate is formed. 

    Which of the following compounds is responsible for the precipitate?

    • CH3CH2CO2-

    • CH3CH2COCH2I

    • CH3CHICOCH3

    • CHI3

    Choose your answer

    2
    1 mark

    The colour of warm acidified potassium dichromate(VI) changes from orange to green when added to compound Y. 1 mol of Y reacts with 2 mol of hydrogen cyanide in the presence of potassium cyanide.

    What could Y be?

    • CH3CH2CH2CHO

    • CH3COCH2COCH3

    • H2C=CHCH2CHO

    • OHCCH2CH2CHO

    Choose your answer

    3
    1 mark

    Hydroxyethanal has the structural formula HOCH2CHO. 

    In an experiment hydroxyethanal is heated under reflux with an excess of acidified potassium dichromate (VI) until no further oxidation takes place.

    What is the skeletal formula of the organic product formed in the experiment?

    • Skeletal formula of HOCH2COOH (glycolic acid), showing partial oxidation of hydroxyethanal where only the aldehyde group has been oxidised to a carboxylic acid
    • Skeletal formula of an organic product with three carbon atoms, showing an incorrect carbon chain length for the oxidation of hydroxyethanal
    • Skeletal formula of HOOCCOOH (ethanedioic acid), the fully oxidised product of hydroxyethanal where both the primary alcohol and aldehyde groups have been oxidised to carboxylic acid groups
    • Skeletal formula of OHCCOOH (glyoxylic acid), showing partial oxidation of hydroxyethanal where only the primary alcohol has been oxidised, leaving the aldehyde group unchanged

    Choose your answer

    4
    1 mark

    Which reagent will give similar results with both propanone and propanal?

    • 2,4-dinitrophenylhydrazine reagent

    • Acidified aqueous potassium dichromate (VI)

    • Fehling’s solution

    • Tollens’ reagent

    Choose your answer

    5
    1 mark

    Carvone is used as a flavouring for spearmint chewing gum.

    Structure of carvone, a six-membered ring compound with a ketone group, an isopropenyl substituent, and a methyl group

    When carvone is heated under reflux with excess hot concentrated acidified potassium manganate(VII) the products carbon dioxide and compound X are formed.

    X contains nine carbon atoms and reacts with 2,4-dinitrophenylhydrazine reagent.

    What is the maximum number of molecules of 2,4-dinitrophenylhydrazine that will react with one molecule of X?

    • 1

    • 2

    • 3

    • 4

    Choose your answer

    6
    1 mark

    When compounds 1, 2 and 3 react with PCl5, hydrogen chloride is evolved. However, only one of the three reacts with 2,4-dinitrophenylhydrazine reagent.

    Which one of the following combinations could be 1, 2 and 3?

    Table showing four combinations (A–D) of three organic compounds with their structural formulae. Each row presents a different set of compounds labelled 1, 2 and 3 for students to evaluate against the criteria given

      Choose your answer

      7
      1 mark

      An organic liquid X gives the following results:

      • Forms an orange precipitate with 2,4-DNPH

      • Does not form a silver mirror with Tollens’ reagent

      • Forms a yellow precipitate with alkaline aqueous iodine

      What is the identity of X?

      • Butan-2-ol

      • Butanone

      • Pentan-3-one

      • Propanal

      Choose your answer

      8
      1 mark

      An organic compound X has a molecular ion peak at m/z = 58 in its mass spectrum.

      Experimental data for compound X is shown in the table below:

      Test

      Observation

      Addition of 2,4-dinitrophenylhydrazine (2,4-DNPH)

      Orange precipitate formed

      Warming with Tollens' reagent

      No visible change

      What is the identity of compound X?

      • CH3CH2CH2CH3

      • CH3CH2CHO

      • CH3CH2COOH

      • CH3COCH3

      Choose your answer

      1
      1 mark

      When HCN reacts with butanal, CH3CH2CH2CHO, product X is formed. If X is then hydrolysed by aqueous acid, product Y is produced.

      When pentanal, CH3CH2CH2CH2CHO, is heated under reflux with acidified potassium dichromate(VI), product Z is formed.

      What is the difference in relative molecular mass of products Y and Z?

      • 12

      • 14

      • 16

      • 18

      Choose your answer

      2
      1 mark

      Hydroxynitriles can be made from carbonyl compounds by generating CN– ions from HCN in the presence of a weak base.

      Reaction scheme showing nucleophilic addition of CN^–^ to a carbonyl compound (C=O) to give a hydroxynitrile product with an OH group and a CN group on the same carbon

      In a similar reaction, –CH2CO2CH3 ions are generated from CH3CO2CH3 by strong bases.

      Which compound can be made from an aldehyde and CH3CO2CH3 in the presence of a strong base?

      • (CH3)2C(OH)CH2CO2CH3

      • CH3CH(OH)CO2CH3

      • CH3CH2CH(OH)CH2CO2CH3

      • CH3CO2CH2CH(OH)CH3

      Choose your answer

      3
      1 mark

      When compound T reacts with its own oxidation product, a sweet-smelling liquid is produced. 

      What is the identity of compound T? 

      • Butan–1–ol

      • Butanal

      • Butanoic acid

      • Butanone

      Choose your answer

      4
      1 mark

      1 mol of CH3COCH2CH2CHO is placed into each of three separate test-tubes.

      An excess of NaBH4 is added to test-tube 1 and an excess of acidified potassium manganate(VII) is added to test-tube 2. No reagent is added to test-tube 3.

      An excess of HCN is then added to each test-tube.

      Which row correctly shows the number of moles of HCN that react with the organic compound in each test-tube?

      test-tube 1

      test-tube 2

      test-tube 3

      A

      0

      1

      2

      B

      0

      2

      2

      C

      1

      1

      2

      D

      2

      1

      0

        Choose your answer