Alkenes (OCR A Level Chemistry)

Exam Questions

4 hours40 questions
11 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

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21 mark

Which of the following compounds will give a positive unsaturation test result with bromine water?

  cyclohexene-skeletal 2-methylbut-2-ene-skeletal 2-methylpentane-skeletal
A
B X
C X
D X

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    31 mark

    Which species will not undergo electrophilic addition with an alkene?

    • HBr

    • NaOH

    • Br2

    • H2SO4

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    41 mark

    Which pair of chemicals will give a major and minor product when they undergo electrophilic addition?

    • Ethene + hydrogen bromide

    • Propene + bromine

    • But-1-ene + hydrogen bromide

    • But-1-ene + bromine

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    51 mark

    Which is the most stable carbocation intermediate?

    q7-3-4-easy-mcq-alkenes-1

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      61 mark

      Which monomer can form the following addition polymer?

      q9-3-4-easy-mcq-alkenes

      • Propene

      • But-1-ene

      • But-2-ene 

      • Pent-1-ene

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      71 mark

      Consider the reaction between but-1-ene and hydrogen bromide to form the minor product.

      q10-3-4-easy-mcq-alkenes

      Which carbocation is formed in the electrophilic addition mechanism of this reaction?

      q10-3-4-easy-mcq-alkenes-1

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        81 mark

        What is the bond angle around each carbon atom in the double bond of ethene?

        • 90°

        • 109.5°

        • 120°

        • 180°

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        91 mark

        Polyvinyl chloride, PVC, is a common polymer with many everyday uses.

        q8-3-4-easy-mcq-alkenes

        What is the correct IUPAC name for PVC?

        • Poly(chloroethane)

        • Poly(ethane chloride)

        • Poly(chloroethene)

        • Poly(ethene chloride)

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        101 mark

        Ethene can undergo electrophilic addition to form ethanol.

        What are the conditions needed for this reaction?

        • Hydrogen, heat and nickel catalyst

        • Steam, heat and nickel catalyst

        • Hydrogen, heat and acid catalyst

        • Steam, heat and acid catalyst

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        11 mark

        Which compound is formed when pent-2-ene reacts with bromine?

        • 1,1-dibromopentane

        • 1,2-dibromopentane

        • 2,2-dibromopentane

        • 2,3-dibromopentane

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        21 mark

        Which molecule is a Z-isomer?

        A Ojr2I0CG_isomer-option-a
        B OixKKci6_isomer-option-b
        C g79KfDOa_isomer-option-c
        D SBJe5YbZ_isomer-option-d

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          31 mark

          What is the systematic name of the compound below?

          e-2-bromobut-2-ene

          • E-2-bromobut-2-ene

          • Z-2-bromobut-2-ene

          • E-1,2-dimethyl-1-bromoethene

          • Z-1,2-dimethyl-1-bromoethene

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          41 mark

          The displayed formula for a hydrocarbon is shown below.

          displayed-hydrocarbon

          How many σ and π bonds are present in a molecule of this hydrocarbon?

            σ bonds  π bonds
          A 2 4
          B 10 2
          C 10 4
          D 12 2

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            51 mark

            Three of the following displayed formulae represent the same isomer of C3H4Cl2 but one structure represents a different isomer, X.
            Which displayed formula represents X?

            A 2xi10vCL_chloroalkene-option-a
            B PRei1cHd_chloroalkene-option-b
            C LdEqcfAQ_chloroalkene-option-c
            D JxIbubqv_chloroalkene-option-d

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              61 mark

              A section of a polymer chain is shown below.

              addition-polymer-section

              Identify the monomer that would give rise to this section of addition polymer.

              • E-But-2-ene

              • Z-But-2-ene

              • Methylpropene

              • Propene

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              71 mark

              A molecule of a polymer contained the sequence shown.


              addition-polymer-section-2

              Which monomer could produce this polymer by addition polymerisation?

              • CH3CCl =CHCl

              • CH2=CHCl

              • CHCl =CHCl

              • CH3CCl =CH2

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              81 mark

              Isomers X and Y both react with HBr.


              x-and-y

              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

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                91 mark

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

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

                A wpb~vvSe_limonene-option-a
                B ymI2zxfm_limonene-option-b
                C pooXk3RH_limonene-option-c
                D jMxD~NSu_limonene-option-d

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                  101 mark

                  Which compound is produced in the reaction between hex-2-ene and steam?

                  • (CH3)2CHCH2CH2CH2OH

                  • CH3CH2CH2CH2CH(OH)CH3

                  • CH3CH2CH(OH)CH2CH3

                  • CH3CH2CH2CH2CH2CH2OH

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                  11 mark

                  The molecule below has two double bonds, labelled 1 and 2.

                  C2na6PgP_e-z-isomers

                  The arrangement around each double bond can be identified as E or Z.

                  Which row in the table is correct for double bond 1 and double bond 2?

                    Double bond 1  Double bond 2 
                  A E Z
                  B Z E
                  C E E
                  D Z Z

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                    21 mark

                    There are many structural isomers with the molecular formula C4H7Br, including the following:

                    c4h7br-isomers

                    Of the isomers shown, determine how many

                    • Show E/Z isomerism.
                    • Show optical isomerism.
                      Show E/Z isomerism Show optical isomerism
                    A 2 1
                    B 2 3
                    C 3 1
                    D 3 3

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                      31 mark

                      Which statement about propene is correct?

                      • The C-C bond is half as strong as the C=C bond.

                      • It has E/Z isomers due to restricted rotation around the C=C bond. 

                      • It undergoes nucleophilic addition with bromine.

                      • It is more reactive than propane due to the strain on the ? bond.

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                      41 mark

                      Which molecule does not show E/Z isomerism?

                      • 3-methylpent-2-ene

                      • 2,4-dimethylpent-2-ene

                      • 2,2-dimethylhex-3-ene

                      • 1-Propen-1-ylbenzene

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                      51 mark

                      Which statement(s) is/are correct about 2-methylbut-1-ene?

                      1. In the reaction with steam and H2SO4, the major product formed is 2-methylbutan-2-ol.
                      2. During hydrohalogenation, the C=C bond induces a temporary dipole in the hydrogen halide.
                      3. The polymer formed can be hydrolysed in the presence of H2SO4.
                      • 1, 2 and 3

                      • Only 1 and 2

                      • Only 2 and 3

                      • Only 1

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