Halogenoalkanes

• Why is the C-X bond polar when X is a halogen?

  Halogen is more electronegative than carbon
• What forces are present in halogenoalkanes?

  • Dipole-dipole forces
  • Van der Waals forces
• How does boiling point change in halogenoalkanes going down the group?

  It increases
• Why do halogenoalkanes have higher boiling points than alkanes of the same chain length?


  They have higher molecular masses and are more polar
• What is a nucleophile?

  An electron pair donor
• What is the most reactive C-X bond?

  C-I due to larger atomic radius and increased shielding
• What are the conditions for nucleophilic substitution?

  Aqueous at room temperature
• In nucleophilic substitution, what role does OH- play?

  It acts as a nucleophile
• In elimination reactions, what role does OH- play?

  It acts as a base
• What are the conditions for elimination reactions?

  Hot ethanolic KOH
• What is a nucleophile?

  An electron pair donor
• Why is ozone important?

  It absorbs UV radiation
• What are the two equations for the decomposition of ozone?

  • Cl$\cdot$ + O3 -> ClO$\cdot$ + O2
  • ClO$\cdot$ + O3 -> 2O2 + Cl$\cdot$
• What is produced in the nucleophilic substitution reaction with a cyanide nucleophile?

  A nitrile
• What are the conditions for nucleophilic substitution with a :OH-?

  Warm

  Aqueous

  Alcoholic
• What are the conditions required for the nucleophilic substitution reaction with KCN?

  • Warm
  • Aqueous
  • Alcoholic
• What are the conditions required for the nucleophilic substitution reaction with ammonia?

  • Excess concentrated ammonia solution
  • Ethanol
  • Pressure
• How does OH- act as a base?

  By removing a proton from a haloalkane.
• What are the conditions of an elimination reaction with KOH?

  Ethanolic

  Hot
• What are the products of an elimination reaction with KOH with bromoethane?


  Ethene

  KBr

  H2O
• Do primary haloalkanes tend to react by elimination or substitution?


  Substitution
• How do tertiary haloalkanes tend to react?

  Elimination