uses of chlorine

• What are disproportionation reactions?

  Reactions where a substance is oxidized and reduced
• When does disproportionation occur?

  When the oxidation number both increases and decreases
• What happens to chlorine gas when it reacts with water?

  It undergoes disproportionation
• In the reaction of chlorine gas with water, what are the products formed?

  HCl and HClO
• What is the change in oxidation number of chlorine in HClO?

  Increases from 0 to +1
• What is the change in oxidation number of chlorine in HCl?

  Decreases from 0 to -1
• What is the reaction when chlorine gas is bubbled through water?

  Cl2(g) + H2O(l) ➔ HCl(aq) + HClO
• What does hypochlorous acid (HClO) dissociate into?

  H+ and ClO- ions
• How do hypochlorite ions (ClO-) function in water treatment?

  They kill microorganisms in the water
• What happens to hypochlorite ions in sunlight?

  They deplete due to reaction with chlorine
• What is the reaction of chlorine gas with water in sunlight?

  Cl2(g) + 2H2O(l) ➔ 2HCl(aq) + 1/2O2(g)
• Why do swimming pools require regular additions of chlorine?

  To maintain effective disinfection
• What are the benefits of using chlorine for water disinfection?

  • Kills disease-causing microorganisms
  • Prevents reinfection in the supply
  • Removes bad tastes, smells, and discoloration
• What are the risks of using chlorine for water disinfection?

  • Causes severe irritation if inhaled
  • Forms carcinogenic chlorinated hydrocarbons with organics
• What alternatives to chlorine are sometimes used for disinfection?

  Ozone and ultraviolet light
• What is a disadvantage of using ozone for disinfection?

  It is expensive and decays rapidly
• What is a disadvantage of using UV light for disinfection?

  Less effective in cloudy water
• What is produced when chlorine gas is mixed with sodium hydroxide?

  Sodium chlorate(I) solution (NaClO)
• What is the reaction for making bleach through disproportionation?

  Cl2(g) + 2NaOH(aq) ➔ NaClO(aq) + NaCl(aq) + H2O(l)
• What do chlorate(I) ions (ClO-) do in bleach?

  Act as oxidizing agents to kill bacteria
• What are the uses of bleach made from chlorine?

  • Disinfecting surfaces
  • Cleaning purposes
  • Killing bacteria