Lesson 3.3.2.4

3.3.2.4 Chlorination of alkanes Quiz: AQA Chemistry, Unit 3

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.3.2.4, Chlorination of alkanes: 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. What reagents and conditions are needed for the reaction of methane with chlorine?

    • Chlorine and ultraviolet light
    • Aqueous sodium hydroxide at room temperature
    • Chlorine and a nickel catalyst at 200 C
    • Hydrogen chloride and water

  2. What type of mechanism is the reaction of methane with chlorine?

    • Elimination
    • Electrophilic addition
    • Free-radical substitution
    • Nucleophilic substitution

  3. Which step is the initiation step in the chlorination of methane?

    • Cl + Cl -> Cl2
    • CH3 + Cl -> CH3Cl
    • CH4 -> CH3 + H radicals
    • Cl2 -> 2Cl radicals

  4. Which step is a termination step in the chlorination of methane?

    • CH3 radical + Cl radical -> CH3Cl
    • Cl2 -> 2Cl radicals
    • CH3Cl + Cl2 -> CH2Cl2 + HCl
    • CH4 + Cl radical -> CH3 radical + HCl

  5. Which product is formed in a propagation step in the chlorination of methane?

    • CH4
    • Ethane only
    • HCl
    • Cl2

  6. Why does chlorination of methane give a mixture of products?

    • The products are always ionic
    • The methane is always converted to pure chloromethane
    • Further substitution of chloromethane can occur, giving CH2Cl2, CHCl3 and CCl4
    • Chlorine reacts only with hydrogen

  7. What is the name of the product formed from CH4 + Cl2 with one substitution?

    • Dichloromethane
    • Tetrachloromethane
    • Chloroethane
    • Chloromethane

  8. Which compound is formed when all four hydrogens of methane are replaced by chlorine?

    • Tetrachloromethane
    • Dichloroethane
    • Trichloroethene
    • Chloromethane

  9. Which of these is an example of free-radical termination with an alkane?

    • Cl2 -> 2Cl
    • CH4 + O2 -> CO2 + H2O
    • CH4 + Cl radical -> CH3 radical + HCl
    • CH3 radical + CH3 radical -> C2H6

  10. In a free-radical mechanism, what does the chain propagation depend on?

    • Each step producing a radical that continues the chain
    • Ionic intermediates such as carbocations
    • Each step consuming all radicals
    • A catalyst that is consumed completely

  11. What is the balanced equation for the formation of chloromethane from methane?

    • CH4 + 2Cl2 -> CH2Cl2 + 2HCl
    • CH4 + Cl2 -> CH3Cl + HCl
    • CH4 + Cl2 -> CH3Cl + H2
    • CH4 + Cl2 -> CH2Cl2 + H2

  12. Why is UV light needed for the chlorination of methane?

    • It converts methane into ethene
    • It makes the reaction exothermic only
    • It provides the energy to split Cl2 into radicals
    • It removes the HCl formed

  13. Which product is the most useful as a solvent in the chlorination series?

    • Methane
    • Ethene
    • Methanol
    • Tetrachloromethane

  14. What is a radical in the context of the chlorination mechanism?

    • A metal atom in a complex
    • An ion with a full octet
    • A species with an unpaired electron, such as Cl or CH3
    • A stable molecule such as HCl

  15. Which of these is the correct free-radical equation for a propagation step using CH3Cl?

    • CH3Cl + H+ -> CH4 + Cl+
    • CH3Cl -> CH3+ + Cl-
    • CH3Cl + OH- -> CH3OH + Cl-
    • CH3Cl + Cl radical -> CH2Cl radical + HCl

  16. Why does the chlorination of methane not stop at one substitution when excess chlorine is present?

    • The reaction is reversible at room temperature
    • Chloromethane still has hydrogens that can be substituted by radicals
    • Chloromethane is ionic and cannot react
    • Chlorine is a catalyst that stops the reaction

  17. Which property of a radical makes it highly reactive?

    • It has a full octet
    • It is always an anion
    • It has no electrons
    • It has an unpaired electron

  18. Which compound is a by-product in the chlorination of methane at every substitution step?

    • HCl
    • Cl2
    • CH4
    • CCl4 only

  19. Explain why a chain reaction is described for the chlorination of methane.

    • Each step produces a new initiator that stops the reaction
    • The reaction involves a chain of ionic salts
    • Radicals are regenerated in propagation steps, so the process continues without new initiation
    • Chlorine atoms are never regenerated during the reaction

  20. Explain why termination is less common than propagation during chlorination of methane.

    • Methane molecules absorb all radicals
    • Radicals are present in low concentration, so collisions between two radicals are less likely than radical-molecule reactions
    • Radicals are always removed by UV light before they react
    • Termination requires a catalyst that is never present

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