A LevelChemistryOCRExam Questions4. Core Organic ChemistryOrganic Synthesis

Organic Synthesis (OCR A Level Chemistry A): Exam Questions

Exam code: H432

3 hours40 questions

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Organic Synthesis

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1
1 mark

Which statement about heating under reflux is correct?

  • Organic liquids can be heated without evaporation taking place.

  • Organic liquids can be maintained at their boiling point for extended periods.

  • Heating is carried out using a water bath.

  • The apparatus is closed to prevent the loss of any materials.

Choose your answer

2
1 mark

Which of the following can be done with the aid of a separating funnel?

Neutralise acidic impurities

Dry organic liquids

Separate miscible liquids

A

✓

✓

✓

B

✓

✓

✗

C

✗

✓

✓

D

✓

✗

✗

    Choose your answer

    3
    1 mark

    What reaction could the following equipment be used for?

    Distillation equipment

    • Preparing a carboxylic acid.

    • Cracking an alkane.

    • Oxidising an alcohol.

    • Halogenation of an alkene.

    Choose your answer

    4
    1 mark

    The diagram shows a distillation apparatus.

    Distillation equipment, with a label X for the piece of equipment designed to measure temperature

    What is the purpose of the part labelled X?

    • To check the boiling point of the reaction mixture.

    • To separate the distillate from the reaction mixture.

    • To check the purity of the distillate.

    • To prevent gases from escaping.

    Choose your answer

    5
    1 mark

    Which type of reaction has the greatest atom economy?

    • Substitution

    • Hydrolysis

    • Elimination

    • Addition

    Choose your answer

    6
    1 mark

    Which reaction occurs when ethane and chlorine are mixed in the presence of ultraviolet radiation?

    • A free-radical substitution with hydrogen produced

    • A free-radical substitution with hydrogen chloride produced

    • A free-radical substitution with no gas produced

    • A nucleophilic substitution with hydrogen chloride produced

    Choose your answer

    7
    1 mark

    This molecule is responsible for the flavour of spearmint chewing gum.

    Chemical structure of carvone. Label 1 pointing at the C=C of the ring structure. Label 2 pointing at the C=O of the ring structure

    What is a true statement about the functional groups 1 or 2?

    • 1 will undergo electrophilic addition

    • 1 will undergo electrophilic substitution

    • 2 will undergo nucleophilic substitution

    • 2 will undergo electrophilic substitution

    Choose your answer

    8
    1 mark

    The addition of hydrogen bromide, HBr, to pent-1-ene, CH3CH2CH2CH=CH2 , produces

    • 1-bromopentane

    • 2-bromopentane

    • 1,2-dibromopentane

    • A mixture of 1-bromopentane and 2-bromopentane

    Choose your answer

    9
    1 mark

    A reaction scheme is shown below.

    Chemical reaction diagram: Alkene reacts with HBr, forming two possible products. Product 1 has bromine on end carbon; Product 2 has bromine on middle carbon.

    Which of the following statements is correct?

    • Product 1 is the major product

    • Product 2 is the major product

    •  A 50:50 mixture of the two products is formed

    • The bromine acts as an electrophile

    Choose your answer

    10
    1 mark

    A reaction sequence is shown below.

    chloroethane \overset{\text{reaction 1}}{\rightarrow} ethanol \overset{\text{reaction 2}}{\rightarrow} ethanal

    Identify reaction 1 and reaction 2.

    Reaction 1

    Reaction 2

    A

    Nucleophilic Addition

    Oxidation

    B

    Nucleophilic Substitution

    Oxidation

    C

    Nucleophilic Addition

    Reduction

    D

    Nucleophilic Substitution

    Reduction

      Choose your answer

      1
      1 mark

      Crotonaldehyde, CH3CH=CHCHO, occurs in soybean oils and can be formed from its alcohol, CH3CH=CHCH2OH.

      What are the reagents and conditions required to form crotonaldehyde from its alcohol?

      Condition

      Reagent

      A

      Reflux

      K2Cr2O7

      B

      Reflux

      K2Cr2O7 / H+

      C

      Distillation

      K2Cr2O7 / H+

      D

      Distillation

      K2Cr2O7

        Choose your answer

        2
        1 mark

        Which reagent can be used to dry a damp sample of ethyl ethanoate?

        • Saturated sodium carbonate solution.

        • Anhydrous sodium sulfate.

        • Concentrated sulfuric acid.

        • Aluminium oxide.

        Choose your answer

        3
        1 mark

        Which compound contains an aldehyde functional group?

        • CH3CH2CH2COOCH3 

        • CH3CH2CH2COCH3 

        • CH3CH2OCH2CH3 

        • CH3CH2CH2CH2CHO

        Choose your answer

        4
        1 mark

        Which compound is a tertiary haloalkane?

        • CH3CH2CH2Cl

        • CH3CH2CH(CH3)Br

        • C(CH3)3Cl

        • CH3CHBrCH2CH3 

        Choose your answer

        5
        1 mark

        A reaction sequence is shown below.

        CH3CH2CH2CH2Br \overset{\text{Step 1}}{\rightarrow} CH3CH2CH2CH2OH \overset{\text{Step 2}}{\rightarrow} CH3CH2CH2COOH

        What is the correct classification of the steps?

        Step 1

        Step 2

        A

        Substitution

        Addition

        B

        Oxidation

        Substitution

        C

        Addition

        Oxidation

        D

        Substitution

        Oxidation

          Choose your answer

          6
          1 mark

          A reaction sequence is shown below.

          1-chloropropane rightwards arrow with Step space 1 on top Propan-1-ol rightwards arrow with Step space 2 on top Propanal

          What reagents and conditions are required for each step?

           

          Step 1

          Step 2

          A

          Reflux with NaOH (aq)

          Distil with K2Cr2O7 

          B

          Reflux with NaCN (aq)

          Reflux with K2Cr2O7 / H+ 

          C

          Distil with K2Cr2O7 / H+ 

          Reflux with NaCN (aq)

          D

          Reflux with NaOH (aq)

          Distil with K2Cr2O7 / H+ 

            Choose your answer

            7
            1 mark

            Butanone can be produced from but-2-ene by the following two-step synthesis.

            But-2-ene \overset{\text{Step 1}}{\rightarrow} Intermediate \overset{\text{Step 2}}{\rightarrow} Butanone

            Step 1 uses a phosphoric acid catalyst and steam.

            What is the intermediate?

            • Butan-1-ol

            • Butan-2-ol

            • Butan-2,3-diol

            • Butanoic acid

            Choose your answer

            8
            1 mark

            The structure of a compound used to treat attention deficit hyperactivity disorder is shown below.

            Methyl phenyl(piperidin-2-yl)acetate structure

            Which functional group(s) is/are in a molecule of the compound?

            1. Amine

            2. Carboxylic acid

            3. Ketone

            • 1, 2 and 3

            • Only 1 and 2

            • Only 2 and 3

            • Only 1

            Choose your answer

            9
            1 mark

            Ethane-1,2-diol can be made from ethene using the following two-stage synthetic route.

            H2C=CH2 \overset{\text{Step 1}}{\rightarrow} BrCH2CH2Br \overset{\text{Step 2}}{\rightarrow} CH2OHCH2OH

            What reagents are required for each step?

            Step 1

            Step 2

            A

            Excess HBr (aq)

            Ethanolic NaOH

            B

            Br2

            C2H5OH (l)

            C

            H2 (g) with a Ni catalyst

            NaOH (aq)

            D

            Br2

            NaOH (aq)

              Choose your answer

              10
              1 mark

              Ethane-1,2-diol can be made from ethene using the following two-stage synthetic route.

              H2C=CH2 \overset{\text{Step 1}}{\rightarrow} BrCH2CH2Br \overset{\text{Step 2}}{\rightarrow} CH2OHCH2OH

              Which type of reaction mechanism is involved in each step?

              Step 1

              Step 2

              A

              Electrophilic substitution

              Electrophilic addition

              B

              Electrophilic addition

              Nucleophilic substitution

              C

              Electrophilic addition

              Nucleophilic addition

              D

              Nucleophilic substitution

              Electrophilic addition

                Choose your answer

                11
                1 mark

                A student intends to separate a mixture of water (boiling point 100 °C) and propanoic acid (boiling point 141 °C) by distillation.

                Which diagram shows the apparatus correctly set up for this procedure?

                • Diagram of a distillation setup with a round bottomed flask heated at the base, a thermometer, and a Liebig condenser with labelled water flow.
                • Distillation setup with a round-bottom flask, thermometer, and Liebig condenser. Water flows into and out of the condenser for cooling.
                • Laboratory distillation setup with a round-bottom flask, thermometer, and Liebig condenser with labelled water in and out points.
                • Scientific distillation setup with a round-bottomed flask heated below, thermometer above, and Liebig condenser with water inlet and outlet.

                Choose your answer

                1
                1 mark

                Which statement(s) about the preparation and purification of an organic liquid is/are correct?

                1. Reflux is used for the condensation reaction between an alcohol and a carboxylic acid.

                2. In a separating funnel, adding water will identify the organic layer as it will decrease in volume.

                3. A Bunsen burner must be used in reflux because it requires more vigorous heating.

                • 1, 2 and 3

                • Only 1 and 2

                • Only 2 and 3

                • Only 1

                Choose your answer

                2
                1 mark

                A two-stage synthesis is shown below.

                Methylbutane \overset{\text{Step 1}}{\rightarrow} Intermediate X \overset{\text{Step 2}}{\rightarrow} Alcohol

                When the alcohol is treated with acidified potassium dichromate(VI), the solution remains orange.

                Which row correctly identifies intermediate X and the reagents and conditions of Step 2?

                Intermediate X

                Reagents and conditions of Step 2

                A

                2-chloro-2-methylbutane

                NaOH (aq) / reflux

                B

                2-methylbut-1-ene

                NaOH (aq) / reflux

                C

                3-methylbut-1-ene

                Steam and H2SO4 / heat

                D

                2-chloro-3-methylbutane

                Steam and H2SO4 / heat

                  Choose your answer

                  3
                  1 mark

                  1-chlorobutane can be made by the following multistep process.

                  Which of the following reagents is not suitable for the indicated step?

                  vuqMYbi5_ocr-as-4-6h-mcq-q3-reaction-sequence

                  • Step 1 hot K2Cr2O7/H2SO4

                  • Step 2 hot Al2O3

                  • Step 3 H2 and Ni catalyst

                  • Step 4 Cl2 and UV light

                  Choose your answer

                  4
                  1 mark

                  Which of the following types of reaction is not involved in the sequence below?

                  rJyXzIce_ocr-as-4-6h-mcq-q4-reaction-sequence

                  • Electrophilic addition

                  • Elimination

                  • Nucleophilic substitution

                  • Free radical substitution 

                  Choose your answer

                  5
                  1 mark

                  Which statement(s) is/are correct?

                  1. The sequence alkene → alcohol → aldehyde has a higher yield than alkene → haloalkane → alcohol → aldehyde.

                  2. A nucleophile will attack a haloalkane because the halogen atom is more electronegative than the hydrogen atoms.

                  3. Polyethene is not degraded by NaOH because of the electron-rich carbon-carbon double bonds.

                  • 1, 2 and 3

                  • Only 1 and 2

                  • Only 2 and 3

                  • Only 1

                  Choose your answer