Group 7 Key equations

• What is the equation for the reaction of chlorine with water?

  • Cl2 + H2O -> HClO + HCl
  • Sterilises bacteria
• What is the reaction of chlorine in sunlight?

  • 2Cl2 + 2H2O -> 4HCl + O2
• What is the equation for the reaction of chlorine with sulphuric acid and what is chlorines role?

  • NaCl + H2SO4 -> HCl + NaHSO4
  • Acts as a base
  • Produces white fumes of HCl
• What is the reaction of bromine with sulphuric acid?

  • NaBr + H2SO4 -> HBr + NaHSO4
  • Produces white fumes of HBr
• What is the redox reaction of bromine with sulphuric acid?

  • 2HBr + H2SO4 -> Br2 + SO2 + 2H2O
  • Br is oxidised from -1 to 0
  • S is reduced from +6 to +4
• What is the equation for iodine with sulphuric acid?

  • NaI + H2SO4 -> HI + NaHSO4
  • White fumes of HI
• What is the redox reaction of iodine with sulphuric acid where a colourless gas is produced?

  • 2HI + H2SO4 -> I2 + SO2 + 2H2O
  • Black solid of I2 produced
  • I oxidised from -1 to 0
  • S reduced from +6 to +4
• What is the redox reaction of iodine with sulphuric acid that produces a yellow solid?

  • 6HI + H2SO4 -> 3I2 + S + 4H2O
  • Yellow solid of S/Purple fumes of 3I2
  • I oxidised from -1 to 0
  • S reduced from +6 to 0
• What is the redox reaction with iodine that produces a gas with an egg smell?

  • 8HI + H2SO4 -> 4I2 + H2S + 4H2O
  • H2S gas with a bad egg smell
  • I oxidised from -1 to 0
  • S reduced from +6 to -2