Alkenes

• Alkenes undergo electrophilic addition reactions, where electrophiles attack the double bond.
• Common electrophiles used in the addition reactions of alkenes include HBr, Br2, and H2SO4.
• The reaction mechanism of electrophilic addition involves the formation of a carbocation, which is a carbon atom with a positive charge.
• The stability of the carbocation determines the major product formed in an addition reaction.
• Alkenes are unsaturated hydrocarbons that contain a carbon-carbon double bond.
• Alkenes have a high electron density, making them susceptible to attack from electrophiles.
• Bromine water can be used to identify the presence of a double bond in alkenes, turning the solution from orange-brown to colorless.
• Addition polymers are produced from alkenes by breaking the double bond to form a repeating unit.
• The reaction conditions used in the production of addition polymers can be altered to give the polymers different properties.
• Polymers, such as poly(ethene) (used in shopping bags), are unreactive and non-biodegradable.
• addition reaction

  • number of substituents (group that replaces a H on the carbon chain) increases
  • double bond converted to single bond
  • two molecules form one molecule
• a major product has a secondary or tertiary carbocation. carbocations are more stable when their positively charged carbons arec bonded to more alkyl neighbours.