Reactions of alkenes

• Alkanes and cycloalkanes


  • Saturated
  • Singular (C-C)
• Alkenes


  • Unsaturated
  • Double bond (C=C)
  • Contain one carbon to carbon double bond
• Alkyne


  • =C=C
  • Triple bond
• Adding bromine


  1. To a saturated hydrocarbon, there is no reaction

  2. To an unsaturated hydrocarbon, bromine solution is immediately decolourised
• Bromine solution


  Used to distinguish an unsaturated compound from a saturated compound
• Alkenes


  More reactive than alkanes and cycloalkanes because they have a double bond
• Alkenes


  Can participate in addition reactions
• Alkanes, alkenes and cycloalkanes


  Undergo combustion reactions with oxygen
• Addition reaction


  The double bond of the alkene partially breaks when the reactant molecule attacks and adds on across it
• Types of addition reactions

  • Hydrogenation
  • Halogenation
  • Hydration
• Hydrogenation


  Addition of hydrogen (H2)
• Halogenation


  Addition of a halogen (e.g. HCL / Cl2)
• Hydration


  Addition of water (H - OH)