A LevelChemistryOCRExam Questions6. Organic Chemistry & AnalysisExtending Carbon Chains

Extending Carbon Chains (OCR A Level Chemistry A): Exam Questions

Exam code: H432

2 hours28 questions

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Extending Carbon Chains

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1
1 mark

Haloalkanes react with CN– to form nitriles, for example:

CH3CHBrCH3 + CN– → CH3CH(CH3)CN  +  Br–

What is the correct mechanism for this reaction?

  • Electrophillic substitution

  • Free radical substitution  

  • Nucleophilic addition  

  • Nucleophilic substitution

Choose your answer

2
1 mark

Which statement(s) about the hydrolysis of nitriles is/are correct?

  1. Acidic hydrolysis forms a carboxylic acid and an ammonium salt.

  2. Alkaline hydrolysis using NaOH forms a sodium carboxylate salt and ammonia.

  3. Obtaining a carboxylic acid by alkaline hydrolysis requires a subsequent acidification step.

  • 1, 2 and 3

  • Only 1 and 2

  • Only 2 and 3

  • Only 1

Choose your answer

3
1 mark

What is the correct two-step synthesis to produce 2-hydroxypropanenitrile from ethanol?

Step 1

Step 2

A

NaCN (aq)/H+ (aq)

K2Cr2O7/H2SO4, distil

B

K2Cr2O7/H2SO4, distil

NaCN (aq)/H+ (aq)

C

NaCl/H2SO4

NaCN in ethanol

D

NaCN in ethanol

NaCN (aq)/H+ (aq)

    Choose your answer

    4
    1 mark

    Which of the following reactions form a carbon–carbon bond?

    1. Heating benzene with chloroethane in the presence of an AlCl3 catalyst.

    2. Heating chloroethane under reflux with potassium cyanide in ethanol.

    3. Heating propanenitrile with hydrogen and a nickel catalyst.

    • 1, 2 and 3

    • Only 1 and 2

    • Only 2 and 3

    • Only 1

    Choose your answer

    5
    1 mark

    Propanone reacts with NaCN (aq)/H+ (aq) to form compound X, as shown.

    ch3coch3-and-hcn-mechanism

    What is the systematic name of compound X?

    • 2-hydroxy-2-methylbutanenitrile

    • 2-methylbutanenitrile

    • 2-hydroxy-2-methylpropanenitrile

    • 2-methylpropanenitrile

    Choose your answer

    1
    1 mark

    Which equation does not represent the formation of an electrophile?

    • CH3CH2Cl + AlCl3 → CH3CH3+ + AlCl4-

    • HNO3 + 2H2SO4 → NO2+ + H3O+ + 2HSO4-

    • CH3COCl + AlCl3 → CH3CO+ + AlCl4-

    • CH3Br + AlBr3 → CH3+ + AlBr4-

    Choose your answer

    2
    1 mark

    Which of the arrow(s) in the following mechanism is / are correct? 

    ocr-a2-mcqs-m-6-7-q2

    • 1, 2 and 3

    • 1 and 2

    • 2 and 3

    • Only 1

    Choose your answer

    3
    1 mark

    Which organic coompound is not a product of the nucleophilic substitution of 1-bromobutane?

    • Butan-1-ol

    • Pentanenitrile

    • But-1-ene

    • 1-aminobutane

    Choose your answer

    4
    1 mark

    Which set of reagents are required for the formation of 2-hydroxy-5-methylhexanenitrile? 

    • 1-chloropentan-2-ol and NH3 / ethanol 

    • 4-methylpentanal and KCN (aq) / H+ (aq)

    • 2-hydroxyhexamine and LiAlH4

    • 5-methylhexanal and KCN (aq) 

    Choose your answer

    5
    1 mark

    Which of the following reactions will form propanoic acid?

    1. Propanenitrile and HCl (aq)

    2. 2-methylpropan-2-ol, K2Cr2O7 and concentrated sulfuric acid

    3. Propyl propanoate and NaOH (aq)

    • 1, 2 and 3

    • 1 and 2

    • 2 and 3

    • 1 only 

    Choose your answer

    1
    1 mark

    Which compound would not form an optically active product when reacted with a cyanide reagent to extend its carbon chain?

    • CH3CH2CH(Br)CH3

    • CH2COCH2CH3

    • CH3CH2CH2CHO

    • CH3C(CH3)(Br)CH3

    Choose your answer

    2
    1 mark

    Lactic acid is formed in the human body during exercise. It can be made in the 2-step process below.

    gqleIBJA_ocr-a2-6-7h-mcq-q2-reaction-sequence

    Which statement(s) is/are correct?

    1. Lactic acid and molecule X are optically active.

    2. Stage 2 is acid hydrolysis and would produce lactic acid and ammonia.

    3. Lactic acid could also be made from molecule Y by the addition of acidified potassium dichromate.

    • 1, 2 and 3

    • Only 1 and 2

    • Only 2 and 3

    • Only 1

    Choose your answer

    3
    1 mark

    Organic molecules take part in many reactions.

    Which row is correct?

    Organic reactant

    Organic product

    Reagents / reaction conditions

    Type of reaction

    A

    Ethanedial

    Butane-1,4-dinitrile

    HCN

    Nucleophilic substitution

    B

    Butane-1,4-dinitrile

    Ethane-1,2-diamine

    LiAlH4 in dry ether

    Reduction

    C

    Benzene

    1-phenylpropan-1-one

    Propanoyl chloride / AlCl3 / Heat

    Electrophilic addition

    D

    Phenylethanone

    1-phenylethan-1-ol

    NaBH4 / H2O

    Reduction

      Choose your answer

      4
      1 mark

      Propanoyl chloride can react with benzene in the presence of AlCl3. The product of this reaction is molecule X.

      Which statement(s) is/are correct?

      1. Molecule X can be converted to 1-phenylpropan-1-ol by reaction with aqueous NaBH4.

      2. Molecule X can be converted to 1-phenylpropan-1-ol by adding H2 in the presence of a nickel catalyst.

      3. For benzene to react with propanoyl chloride, the electrophile AlCl4– must be generated from AlCl3.

      • 1, 2 and 3

      • Only 1 and 2

      • Only 2 and 3

      • Only 1

      Choose your answer

      5
      1 mark

      Benzene reacts with ethanoyl chloride.

      Which statement(s) is/are correct?

      1. The product has a Mr of 120 and forms an orange solution with the addition of acidified potassium dichromate.

      2. The reaction of methylbenzene and ethanoyl chloride would be faster because the methyl group increases the electron density of the ring.

      3. Methylbenzene will react with ethanoyl chloride and produce a mixture of chain isomers.

      • 1, 2 and 3

      • Only 1 and 2

      • Only 2 and 3

      • Only 1

      Choose your answer