Reactions of halogens

• Halogens reaction with group 1 metal:

  2Li (s) + F2 (g) —> 2LiF(s)

  Lithium: Oxidised

  Fluorine: Reduced
• Halogens reaction with group 2 metals:

  Mg (s) + CL2 (g) —> MgCl2 (s)

  Magnesium: Oxidised

  Chlorine: Reduced
• Halogens undergo Disproportination with cold alkalis:

  e.g I2 +NaOHn—> NaOl + Nal +H2O
• Halogens can exist in wide range of oxidation states
• Halogens undergo disproportionation with hot alkalis

  3Cl2 + 6NaOH —> NaClO3+ 5NaCl + 3H2O
• Chlorine and Sodium Hydroxide react to make bleach

  2NaOH (aq) + CL2 —> NaClO (aq) + H2O

  this is disproportionation

  it’s good for toilet cleaning
• Chlorine can be used to kill bacteria

  • Cl2(g) + H2O —> HCl (aq) + HlCO(aq)
  • this is reversible and a disproportionation reaction
  • Hydrochloric acid and hypochlorous acid is prodiced
  • Hypochlorous acid ionizes to make chlorate ions which kill bacteria
  • so adding chlorine to water can make it safe to drink or swim in