Lesson 6B.2

6B.2 Radical substitution of alkanes Quiz: Pearson Edexcel Chemistry, Unit 6

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 6B.2, Radical substitution of alkanes: 20 multiple choice questions for the Pearson Edexcel Chemistry (9CH0), Unit 6: Organic Chemistry I, written with Revision Ninja.

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The 20 questions

  1. What is the defining feature of a chemical radical?

    • Lone pair
    • Positive charge
    • Unpaired electron
    • Negative charge

  2. Which process breaks a covalent bond to form two radicals?

    • Homolytic fission
    • Electrophilic addition
    • Heterolytic fission
    • Nucleophilic substitution

  3. Which equation represents the initiation step in methane chlorination?

    • Cl2 -> 2Cl•
    • CH4 + Cl2 -> CH3Cl + HCl
    • Cl• + CH4 -> CH3• + HCl
    • CH3• + Cl• -> CH3Cl

  4. Which equation represents a propagation step in methane chlorination?

    • Cl• + CH4 -> CH3• + HCl
    • CH3• + Cl• -> CH3Cl
    • CH3• + CH3• -> C2H6
    • Cl2 -> 2Cl•

  5. Which equation represents a termination step in methane chlorination?

    • CH3• + CH3• -> C2H6
    • Cl2 -> 2Cl•
    • Cl• + CH4 -> CH3• + HCl
    • CH4 -> CH3• + H•

  6. Why is ultraviolet light required in the chlorination of methane?

    • Forms chlorine ions
    • Breaks Cl-Cl bonds
    • Protonates methane molecules
    • Breaks C-H bonds

  7. Which chloromethane is formed first in the radical substitution of methane when chlorine is in excess?

    • CHCl3, trichloromethane
    • CH3Cl, chloromethane
    • CCl4, tetrachloromethane
    • CH2Cl2, dichloromethane

  8. What limitation makes radical substitution unsuitable for single haloalkane synthesis?

    • Requires high pressure
    • Reaction is endothermic
    • Only produces alkenes
    • Further substitution occurs

  9. How many different chlorinated products can be formed from the radical chlorination of methane?

    • 5
    • 4
    • 2
    • 3

  10. What happens during a propagation step in a radical mechanism?

    • Forms only ions
    • Forms new radical
    • Creates initial radicals
    • Removes all radicals

  11. What is the major organic product of the reaction between ethane and chlorine in UV light, assuming monosubstitution?

    • Chloroethane, CH3CH2Cl
    • Tetrachloroethane, CHCl2CHCl2
    • Ethene, CH2=CH2
    • Dichloroethane, CH2ClCH2Cl

  12. Which species is the methyl radical?

    • CH4*
    • CH3-
    • CH3*
    • CH3+

  13. Which process produces trace ethane during methane chlorination?

    • Heterolytic bond cleavage
    • Methyl radicals combining
    • Proton transfer
    • Homolytic fission

  14. What type of species is produced by homolytic fission?

    • Carbanions
    • Ions
    • Carbocations
    • Radicals

  15. What is the overall equation for methane monochlorination?

    • 2CH4 + Cl2 -> 2CH3 + Cl2
    • CH4 + Cl2 -> C + 4HCl
    • CH3Cl + Cl2 -> CH2Cl2 + HCl
    • CH4 + Cl2 -> CH3Cl + HCl

  16. Why is the reaction between ethane and chlorine classified as substitution?

    • Molecule split apart
    • Double bond added
    • Water molecule removed
    • Hydrogen atom replaced

  17. Which species is produced in the propagation step between a chlorine radical and methane?

    • A carbene, CH2
    • A chloride ion, Cl-
    • A methyl radical, CH3*
    • A methylium ion, CH3+

  18. What is the systematic IUPAC name of CHCl3?

    • Chloromethane
    • Trichloromethane
    • Dichloromethane
    • Tetrachloromethane

  19. Which species acts as a chain carrier in radical substitution?

    • Carbanion
    • Free radical
    • Electrophile
    • Carbocation

  20. What happens during a termination step in radical substitution?

    • Two radicals combine
    • A bond cleaves
    • A radical reacts
    • Radicals are formed

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