A LevelChemistryCambridge (CIE)Exam Questions14. HydrocarbonsAlkenes

Alkenes (Cambridge (CIE) A Level Chemistry): Exam Questions

Exam code: 9701

2 hours25 questions

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Alkenes

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1
1 mark

Ethene reacts with steam in the presence of phosphoric acid.

C2H4 + H2O → CH3CH2OH

What type of reaction is this?

  • Acid / Base

  • Addition

  • Hydrolysis

  • Substitution

Choose your answer

2
1 mark

When bromine reacts with propene in an organic solvent at room temperature, what is the mechanism by which the bromine attacks the propene?

  • Electrophilic addition

  • Electrophilic substitution

  • Nucleophilic addition

  • Nucleophilic substitution

Choose your answer

3
1 mark

A molecule of a polymer contained the sequence shown.

Structural formula of a linear hydrocarbon chain with alternating hydrogen and chlorine atoms bonded to carbon atoms along the backbone

Which monomer could produce this polymer by addition polymerisation?

  • CH2=CHCl

  • CHCl=CHCl

  • CH3CCl=CH2

  • CH3CCl=CHCl

Choose your answer

1
1 mark

Which reaction would not give propene?

  • Adding excess hot concentrated sulfuric acid to propan-1-ol.

  • Adding warm aqueous sodium hydroxide to 2-bromopropane.

  • Adding warm ethanolic sodium hydroxide to 1-bromopropane.

  • Passing propan-2-ol vapour over heated aluminium oxide.

Choose your answer

2
1 mark

Ethene reacts with aqueous bromine to give two products, CH2BrCH2Br and CH2BrCH2OH. 

Which statement about these products is correct?

  • Both products are obtained in this reaction by electrophilic substitution.

  • Both products are obtained in this reaction by nucleophilic addition.

  • Both products can be hydrolysed to form the same organic compound.

  • Both products can form hydrogen bonds with water.

Choose your answer

3
1 mark

Pent-2-ene, CH3CH2CH=CHCH3, reacts in a similar way to ethene.

Pent-2-ene is reacted with cold, dilute, acidified manganate (VII) ions. 

What will be produced in the greatest amount?

  • CH3CH2CH(OH)CH(OH)CH3

  • CH3CH2COCOCH3

  • a mixture of CH3CH2CH(OH)CH2CH3 and CH3CH2CH2CH(OH)CH3

  • CH3CH2COOH and CH3COOH

Choose your answer

4
1 mark

Isomers X and Y both react with HBr.

Structural formulae of isomers X and Y, both containing C=C double bonds that react with HBr by electrophilic addition

A mixture of X and Y is reacted with HBr.

Which three structures represent three different possible products of this reaction?

A

(CH3)2CHCBr3

(CH3)2CBrCHBr2

CH3CHBrCHBrCH3

B

(CH3)2CHCBr3

(CH3)2CBrCHBr2

CH3CBr2CHBrCH3

C

(CH3)2CBrCBr3

(CH3)2CHCBr3

CH3CBr2CHBrCH3

D

(CH3)2CBrCHBr2

CHBr2CBr(CH3)CH3

CH3CHBrCBr2CH3

    Choose your answer

    5
    1 mark

    What is the major product formed when compound Q is warmed with excess HBr?

    Structural formula of compound Q, an organic molecule containing a C=C double bond and one or more hydroxyl groups
    • Structural formula showing product A from reaction of compound Q with excess HBr
    • Structural formula showing product B from reaction of compound Q with excess HBr
    • Structural formula showing product C, the major product with all OH groups replaced by Br and the double bond saturated by HBr addition
    • Structural formula showing product D from reaction of compound Q with excess HBr

    Choose your answer

    6
    1 mark

    The oxidative cleavage of an alkene using hot, concentrated, acidified potassium manganate(VII) results in the complete rupture of the carbon–carbon double bond.

    Which row correctly identifies the final products formed from the specified structural groups?

    Structural group in alkene

    Final products formed

    A

    R–CH=CH–R′

    Two different aldehydes

    B

    CH₂=C(R)₂

    Carbon dioxide and a ketone

    C

    R–CH=CH₂

    A carboxylic acid and methanoic acid

    D

    R–CH=C(R)₂

    A carboxylic acid and an alcohol

      Choose your answer

      7
      1 mark

      A polymer has the repeating unit

      Chemical structure of polyisobutylene, showing a repeating unit with a methyl group branch on a carbon chain.

      Which monomer would produce this polymer by addition polymerisation?

      • CH2=CH2

      • CH2=CH–CH3

      • CH3–CH2–CH2–CH3

      • CH3–CH=CH–CH3

      Choose your answer

      1
      1 mark

      Limonene is an oil formed in the peel of citrus fruits.

      Structural formula of limonene, a cyclic terpene containing a six-membered ring with one endocyclic C=C double bond and an isopropenyl side chain containing a second C=C double bond

      Which product is formed when an excess of bromine, Br2 (l), reacts with limonene at room temperature in the dark?

      • Structural formula showing product A, with bromine added across only one double bond of limonene
      • Structural formula showing product B, an incorrect bromination product of limonene
      • Structural formula showing product C, an incorrect bromination product of limonene
      • Structural formula showing product D, the correct tetrabromo product from addition of excess bromine to both double bonds of limonene

      Choose your answer

      2
      1 mark

      Which isomer of C6H13OH gives the greatest number of different alkenes when it is dehydrated?

      • Structural formula of alcohol A, a primary hexanol isomer
      • Structural formula of hexan-3-ol, a secondary alcohol that gives the greatest number of alkene isomers on dehydration
      • Structural formula of 3-methylpentan-3-ol, a tertiary alcohol giving three alkene isomers on dehydration
      • Structural formula of alcohol D, a primary hexanol isomer

      Choose your answer

      3
      1 mark

      Acrylic acid is produced from propene, a gaseous product of oil refineries.

      Structural formula of acrylic acid (prop-2-enoic acid, CH2=CHCOOH), with bond angles x and y labelled at the sp2 carbon atoms

      Which statement about acrylic acid is not correct?

      • Both bond angles x and y are approximately 120°.

      • It decolourises aqueous bromine.

      • It gives an orange precipitate with 2,4-dinitrophenylhydrazine reagent.

      • It reacts with an alcohol to give an ester.

      Choose your answer

      4
      1 mark

      Which compound has an Mr of 84 and will react with HBr to give a product with an Mr of 164.9?

      • Structural formula of compound A, which is not an alkene and does not react with HBr by electrophilic addition
      • Structural formula of compound B, an alkene with Mr = 84 whose HBr addition product does not have Mr = 164.9
      • Structural formula of compound C, which is not an alkene and does not react with HBr by electrophilic addition
      • Structural formula of hex-3-ene, the alkene with Mr = 84 that reacts with HBr to give 3-bromohexane with Mr = 164.9

      Choose your answer

      5
      1 mark

      Alkane X has molecular formula C4H10.

      X reacts with Cl2 (g) in the presence of ultraviolet light to produce only two different monochloroalkanes, C4H9Cl. Both of these monochloroalkanes produce the same alkene Y, and no other organic products, when they are treated with hot ethanolic KOH.

      What is produced when Y is treated with hot concentrated acidified KMnO4?

      • CO2 and CH3CH2CO2H

      • CO2 and CH3COCH3

      • HCO2H and CH3COCH3

      • CH3CO2H only

      Choose your answer

      6
      1 mark

      The following diagram represents the structure of a possible polymer.

      Structural diagram of a polymer repeating unit in which each backbone carbon atom carries a hydroxyl group

      Which sequence of reactions could be used to produce this polymer?

      • Polymerise ethene followed by hydration.

      • Polymerise ethene followed by oxidation with cold acidified KMnO4.

      • Polymerise 1,2-dichloroethene followed by hydrolysis.

      • Polymerise 1,2-dichloroethene followed by oxidation with cold acidified KMnO4.

      Choose your answer

      7
      1 mark

      Oxidation of an alkene Y gives a diol; further oxidation gives a diketone.

      What could be Y?

      • CH3CH=C(CH3)2

      • (CH3)2CHCH=CH2

      • C6H5CH=CHC6H5

      • (C6H5)2C=CHCH3

      Choose your answer

      8
      1 mark

      In a preparation of ethene, ethanol is added a drop at a time to a heated reagent Y. To purify the ethene it is bubbled through a solution Z and then collected. 

      What could reagent Y and solution Z be?

       

      Reagent Y

      Solution Z

      A

      Acidified K2Cr2O7

      Dilute NaOH

      B

      Concentrated H2SO4

      Dilute H2SO4

      C

      Concentrated H2SO4

      Dilute NaOH

      D

      Ethanolic NaOH

      Concentrated H2SO4

        Choose your answer