.4 Alkenes

• The double bond in alkenes is planar (flat) with bond angles of almost 120
• Electrophile: electron rich double bond found in alkenes attracted to the delta positive atom in electrophile > HBr Br2 H2SO4
• Intermediate formed during electrophilic addition is called a carbocation- positively charged carbon
• The double bond in alkenes is planar (flat) with bond angles of almost 120
• Alkene + hydrogen bromide

  > bromoalkene
• Alkene + bromine > dibromoalkene
• Alkene + sulphuric acid > alkyl hydrogensulfate
• If the mixture that produces alkyl hydrogensulfate is heated, and water is added , the H2SO4 group will be replaced by a OH group and an alcohol is formed.
• Intermediate formed during electrophilic addition is called a carbocation (positively charged carbon)
• Carbocations: Positively charged carbon atoms with 3 covalent bonds rather than 4
• If an alkene is symmetrical it will produce one product.]
• If it is unsymmetrical then it will produce a mix of major and minor. >Formed from most stable carbocation intermediate >Primary least stable, tertiary most stable
• Hydration of Ethene: Industrial process, which forms ethanol. The reaction is reversible Catalyst- concentrated phosphoric acid (H3PO4) Pressure- 6000kPa Temp- 300C
• Hydration of Ethene:

  Industrial process, which forms ethanol.

  The reaction is reversible

  Catalyst- concentrated phosphoric acid (H3PO4)

  Pressure- 6000kPa

  Temp- 300C