Electrophilic Addition

• Electrophilic Addition reactions with alkenes always proceed through a carbocation intermediate (ions with a positive charge on carbo).
• Reaction with Halogens

  e.g Br2

  The Electron deficient Br2 forms a temporary dipole as it approaches the electron rich C to C double bond(repels the far b)

  
• Alkenes are highly reactive, as the P electrons form a double bond meaning a high electron density above and below the double bond forming and electron rich double bond
• Reaction with Hydrogen Halides:

  e.g HBr

  Bromine is more electronegative than hydrogen and therefore H acts as the electrophile and is attracted to the Carbon double bonds high electron density

  
• Reaction with Sulphuric acid:

  Alkenes react with Sulphuric acid to form alkyl hydrogen sulphates, and adding water causes hydrolysis forming an alcohol