Lesson 3.3.7

3.3.7 Optical isomerism Quiz: AQA Chemistry, Unit 3

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.3.7, Optical isomerism: 20 multiple choice questions for the AQA Chemistry (7405), Unit 3: Organic chemistry, written with Revision Ninja.

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The 20 questions

  1. How do two enantiomers differ in their physical behaviour?

    • Rotation of light
    • Density
    • Melting point
    • Boiling point

  2. What feature must a molecule contain to show optical isomerism?

    • Planar group
    • Aromatic ring
    • Double bond
    • Chiral centre

  3. What is the term for a pair of non-superimposable mirror images?

    • Structural isomers
    • Enantiomers
    • Diastereomers
    • Conformers

  4. Which option correctly describes the composition of a racemic mixture?

    • Equal enantiomer amounts
    • Structural isomers only
    • Single enantiomer only
    • Unequal enantiomer amounts

  5. Why is a racemic mixture of enantiomers optically inactive?

    • Rotations cancel out
    • No light passes
    • Molecules are symmetrical
    • Light is absorbed

  6. How many chiral centres does 2-chlorobutane contain?

    • 1
    • 2
    • 3
    • 0

  7. Which compound is chiral?

    • 2-bromobutane
    • 2-bromopropane
    • 2-methylpropan-2-ol
    • Propan-2-ol

  8. How many stereoisomers does lactic acid, CH3CH(OH)COOH, have?

    • 1
    • 2
    • 4
    • 3

  9. A molecule has exactly one chiral centre. How many optical isomers does it have?

    • 1
    • 3
    • 4
    • 2

  10. How are two optical isomers related to one another structurally?

    • Positional isomers
    • Superimposable mirror images
    • Non-superimposable mirror images
    • Structural isomers

  11. How many different groups are attached to a chiral carbon atom?

    • Four
    • Three
    • Two
    • Five

  12. What property is measured when plane-polarised light passes through a sugar solution?

    • Refractive index
    • Optical activity
    • UV absorption
    • Electrical conductivity

  13. What does a solid wedge represent in a 3D structural formula?

    • Bond pointing forwards
    • Hydrogen bond
    • Bond pointing backwards
    • Bond in plane

  14. Which property is identical for two pure optical isomers?

    • Melting point
    • Light rotation direction
    • Chiral reactivity
    • Enzyme binding rate

  15. Which alcohol is chiral?

    • 2,2-dimethylpropan-1-ol
    • Butan-1-ol
    • 2-methylpropan-1-ol
    • 2-methylbutan-1-ol

  16. Why does nucleophilic attack on a planar carbonyl group form a racemic mixture?

    • Reversible reaction
    • Catalyst requirement
    • Equal attack probability
    • Steric hindrance

  17. In which way do two enantiomers rotate plane-polarised light?

    • Unequal same direction
    • Equal opposite directions
    • Unequal opposite directions
    • Equal same direction

  18. Which compound has no chiral centre?

    • 2-chlorobutane
    • 2-bromobutane
    • Lactic acid
    • 2-bromopropane

  19. A sample of one enantiomer rotates plane-polarised light by +10 degrees. What rotation does its pure mirror-image enantiomer give?

    • -10 degrees
    • +20 degrees
    • 0 degrees
    • +10 degrees

  20. A mixture contains 75% of the (+) enantiomer and 25% of the (-) enantiomer, where each pure form rotates by 10 degrees. What is the observed net rotation?

    • +5 degrees
    • 0 degrees
    • +10 degrees
    • -5 degrees

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