Lesson 3.2.3.2

3.2.3.2 Uses of chlorine and chlorate(I) Quiz: AQA Chemistry, Unit 2

20 questions

Written by Revision Ninja · Last reviewed 11 October 2026

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Lesson 3.2.3.2, Uses of chlorine and chlorate(I): 20 multiple choice questions for the AQA Chemistry (7405), Unit 2: Inorganic chemistry, written with Revision Ninja.

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The 20 questions

  1. Which compound forms alongside sodium chloride and water when chlorine reacts with cold, dilute NaOH?

    • Sodium sulfate
    • Sodium chlorate(I)
    • Sodium hydride
    • Sodium chlorate(V)

  2. What is the formula of the active ingredient in household bleach?

    • HClO
    • NaClO3
    • NaCl
    • NaClO

  3. Which two acids form when chlorine reacts with water?

    • HCl and H2SO4
    • HCl and HClO
    • HClO and HNO3
    • HCl and HClO3

  4. What gas is produced when chlorine reacts with water in sunlight?

    • Oxygen
    • Nitrogen
    • Hydrogen
    • Carbon dioxide

  5. What is the main purpose of adding chlorine to drinking water?

    • To kill bacteria
    • To prevent corrosion
    • To remove minerals
    • To improve taste

  6. Why is chlorine added to drinking water despite being toxic?

    • It improves taste
    • Benefits outweigh risks
    • It neutralises acidity
    • It is non-toxic

  7. What does society assess when deciding to add chemicals to water supplies?

    • Environmental impact only
    • Chemical purity only
    • Financial cost only
    • Risks and benefits

  8. What household product is formed by reacting chlorine with cold, dilute sodium hydroxide?

    • Bleach
    • Drain cleaner
    • Limescale remover
    • Detergent

  9. What are the oxidation states of chlorine in HCl and HClO respectively?

    • -1 and -1
    • -1 and +1
    • 0 and +1
    • +1 and -1

  10. What type of reaction occurs when chlorine reacts with cold, dilute sodium hydroxide?

    • Electrophilic addition
    • Thermal decomposition
    • Neutralisation
    • Disproportionation

  11. Chlorine has an oxidation state of +1 in chlorate(I) ions. What is its oxidation state in chloride ions?

    • -1
    • -2
    • +1
    • 0

  12. Why must the concentration of chlorine added to drinking water be carefully controlled?

    • Chlorine is toxic
    • Chlorine evaporates quickly
    • Chlorine causes hardness
    • Chlorine neutralises acid

  13. Which chemical property enables chlorine to act as an effective water disinfectant?

    • High thermal stability
    • Strong oxidising power
    • Low electronegativity
    • Strong reducing power

  14. Which compound is added to some public water supplies to reduce tooth decay?

    • Sodium fluoride
    • Sodium chlorate(I)
    • Sodium chloride
    • Sodium hydroxide

  15. What is the primary use of sodium chlorate(I) solution in everyday life?

    • Food preservative
    • Bleach and disinfectant
    • Water softener
    • Fertiliser

  16. Which ionic equation represents chlorine reacting with cold, dilute hydroxide ions?

    • Cl2 + OH- -> Cl- + ClO-
    • 2Cl2 + 2OH- -> 2Cl- + ClO2- + H2O
    • Cl2 + 2OH- -> 2Cl- + H2O
    • Cl2 + 2OH- -> Cl- + ClO- + H2O

  17. Which ion formed when chlorine dissolves in water acts as the disinfectant?

    • Hydroxide ion
    • Chlorate(I) ion
    • Chloride ion
    • Hydronium ion

  18. What is the oxidation state of chlorine in sodium chlorate(I), NaClO?

    • +1
    • -1
    • 0
    • +5

  19. Why does a sodium chlorate(I) solution bleach coloured fabrics?

    • It hydrolyses dyes
    • It neutralises dyes
    • It reduces dyes
    • It oxidises dyes

  20. What is the balanced equation for the reaction of chlorine with water that forms chloride ions and oxygen?

    • 2Cl2 + 2H2O -> 4HCl + O2
    • Cl2 + 2H2O -> HCl + HClO2
    • Cl2 + H2O -> HCl + O2
    • 2Cl2 + H2O -> 2HCl + O2

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