4.1.4 halogen reactions

• Displacement reaction:

  e.g. sodium bromide + chlorine -> sodium chloride + bromine

  • Bromide ions are oxidised (electrons are lost)
  • Chlorine is reduced (electrons are gained)
  • Sodium ions are spectator ions - they do not change in the reaction
• A spectator ion is an ion that doesn't change during a chemical reaction
• Hydrogen halides - when halogens react with hydrogen:

  • covalent compounds
  • hydrogen halides dissolve in water to form acidic solutions, such as hydrofluoric acid, hydrobromic acids and hydroiodic acid
  • hydrogen chloride dissolves in water to form hydrochloric acid.
  • The solutions produce H+ ions, which makes them acidic
• Hydrogen + Chlorine -> hydrogen chloride
• Displacement reaction - more reactive substances replacing less reactive substances from compounds.

  • e.g. sodium bromide + chlorine -> sodium chloride + bromine
• Hydrogen halides are:

  • covalent compounds
  • formed when hydrogen and halogens react