Optical Isomerism (OCR A Level Chemistry A): Exam Questions

Exam code: H432

2 hours30 questions
1
1 mark

Which statement is the most correct for an optical isomer?

  • Four different atoms or groups of atoms around a carbon atom cause optical isomerism

  • Optical isomerism occurs as a result of restricted rotation about a carbon–carbon double bond

  • Optical isomers are superimposable mirror images of each other called enantiomers

  • Optical isomers are molecules that have the same structural formula but have the atoms arranged differently in space

2
1 mark

Which carbon atom is the chiral centre in the following molecule?

1-1
    3
    1 mark

    Which compound contains a chiral carbon?

    • Butanone

    • Butan-2-ol

    • Cyclopentanol

    • Propanal

    4
    1 mark

    Which compound does not contain a chiral carbon?

    2-5
      5
      1 mark

      Some transition metal complexes can show optical isomerism, depending on their geometry and the type of ligands they contain.

      Which of the following complexes will not exhibit optical isomerism?

      • An octahedral complex with six identical monodentate ligands

      • An octahedral complex with three identical bidentate ligands

      • A tetrahedral complex with four different monodentate ligands

      • An octahedral complex with two different bidentate ligands

      1
      1 mark

      Which statement about optical isomerism is correct?

      • Optical isomers have a different arrangement of carbon atoms in the skeleton of the molecule

      • Optical isomers have a different boiling point

      • Optical isomers have the same structural formula

      • Optical isomers have four different atoms attached to the chiral carbon

      2
      1 mark

      Which statement about 2,3-dihydroxybutanedioic acid, shown below, is correct?

      23-dihydroxybutanedioic-acid
      • There are four asymmetric carbon atoms

      • The structure shown rotates plane polarised light to the right

      • 2,3-dihydroxybutanedioic acid is a racemate

      • The molecule has two chiral centres

      3
      1 mark

      Which of the following compounds will produce optical isomers when it undergoes reduction?

      • CH3COCH3

      • CH3CH=CH2

      • CH3CH2COCH3

      • CH3CH2COOH

      4
      1 mark

      What is the number of chiral centres in the molecule below?

      ibuprofen
      • 1

      • 2

      • 3

      • 4

      5
      1 mark

      Ethanal reacts with hydrogen cyanide followed by hydrochloric acid to make 2-hydroxypropanoic acid in the two-step reaction sequence below.

      ethanal-two-step-rxn-optical-isomers

      Which description of the reactants and products is correct?

       

      Reactant

      Product of step 1

      Product of step 2

      A

      Optically active

      Optically active

      Optically active

      B

      Optically inactive

      Mixture of optical isomers

      Mixture of optical isomers

      C

      Optically active

      Optically inactive

      Optically active

      D

      Optically active

      Mixture of optical isomers

      Mixture of optical isomers

        1
        1 mark

        Which compound forms a reduction product capable of exhibiting optical isomerism?

        • CH3CH2CH2COCH3 

        • CH(CH3)2CH2CHO

        • C(CH3)3CHO

        • CH3CH2COCH2CH3 

        2
        1 mark

        Arthrinin-F is a relatively novel compound isolated from fungus.

        Arthrinin-F IB 20.3 MCQs H

        How many chiral centres does Arthrinin-F have in its structure?

        • 14

        • 11

        • 6

        • 4

        3
        1 mark

        Which statement about but-1-en-3-ol, CH2CHCHOHCH3, is not true?

        • It has stereoisomers

        • It will turn an acidified potassium dichromate(VI) solution green

        • It contains a peak at 1650 cm−1 on its IR spectrum

        • It has optical isomers

        4
        1 mark

        N,N-Dimethyl-2-hydroxy-3-methylbutanamide can exist as a pair of optical isomers.

        Which is the correct structure for an N,N-dimethyl-2-hydroxy-3-methylbutanamide enantiomer?

        • nn-dimethyl-2-hydroxy-3-methylbutanamide-option-a

           

        • nn-dimethyl-2-hydroxy-3-methylbutanamide-option-b

           

        • nn-dimethyl-2-hydroxy-3-methylbutanamide-option-c

           

        • nn-dimethyl-2-hydroxy-3-methylbutanamide-option-d

           

        5
        1 mark

        Which compound forms a stereoisomeric product when reduced?

        • CH3CH2CH2=CHCH3

        • CH3CH2CH2CH2CHO

        • CH3CH2C(CH3)=CHCH3

        • CH3CH2CH2COCH3