Optical Isomerism (A-level only) (AQA A Level Chemistry)

Exam Questions

2 hours30 questions
11 mark

Which statement is the most correct for an optical isomer?

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

  • Four different atoms or groups of atoms around a carbon atom causes 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

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21 mark

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

7-1-e-q2-aqa-al-chemistry-mcq

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    31 mark

    Which compound contains a chiral carbon?

    • Propanal

    • Butanone

    • Butan-2-ol

    • Cyclopentanol

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    41 mark

    Which compound does not contain a chiral carbon?

    7-1-e-q4-aqa-al-chemistry-mcq

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      51 mark

      Which of the following can form a racemic mixture?

      • The product of but-1-ene and chlorine

      • The major product of propene and hydrogen chloride

      • The minor product of but-1-ene and hydrogen bromide

      • The product of ethene and bromine

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      11 mark

      Which statement is true about optical isomerism?

      • 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

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      21 mark

      The molecule shown below is called 2,3-dihydroxybutanedioic acid

      7-1-m-q2-aqa-al-chemistry-mcq

      What can be deduced from the structure?

      • 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

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      31 mark

      Ethanal reacts with hydrogen cyanide followed by hydrochloric acid to make 2-hydroxypropanoic acid in a two-step reaction sequence:

      7-1-m-q3-aqa-al-chemistry-mcq

      Which row is true?

       

                   Reactant     

          Product of step 1  

        Product of step 2

        A   

      optically active

      optically active

      optically active

      B

        optically inactive

      racemate

      racemate

      C

      optically active

      optically inactive

      optically active

      D

      optically active

      racemate

      racemate

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        41 mark

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

        • CH3COCH3

        • CH3CH=CH2

        • CH3CH2COCH3

        • CH3CH2COOH

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        51 mark

        Which of the following reactions produces a racemate?

        • CH3CH2COCH3  + HCN

        • CH3CH2CBrCH2  + Br2

        • CH3CH2CHBrCH3  + NaOH

        • CH3CH2CH2CH2OH + H2SO4

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        11 mark

        Which of the following reaction mixtures forms a racemate when the chemicals react?

        • 2-hydroxy-2-methylpropanal with acidified potassium dichromate(VI) solution

        • Ethanol with methanoic acid

        • But-1-ene with bromine water

        • 2-hydroxy-2-methylpropanal with sodium tetrahydridoborate(III) solution

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        21 mark

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

        • CH3CH2COCH2CH3

        • CH3CH2CH2COCH3

        • CH(CH3)2CH2CHO

        • C(CH3)3CHO

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        31 mark

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

        7-1-h-q3-aqa-al-chemistry-mcq

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

        • 4

        • 6

        • 11

        • 14

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        41 mark

        Which one of the following statements about but-3-en-2-ol, CH2CHCHOHCH3, is not true?

        • It has optical isomers

        • It has stereoisomers

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

        • It shows a strong absorption in the infra-red at about 1650 cm−1

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        51 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?

        qNttoDeM_7-1-h-q5-aqa-al-chemistry-mcq

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