Addition Reactions of Alkenes

• What are alkenes classified as?

  Unsaturated hydrocarbons
• What does the term "unsaturated" mean in alkenes?

  They contain at least one carbon-carbon double bond
• What is the functional group of alkenes?

  Carbon-carbon double bond
• Why can alkenes undergo addition reactions?

  The carbon-carbon double bond can open up
• What are the three types of addition reactions for alkenes?

  1. With hydrogen
  2. With water
  3. With halogens
• What happens when hydrogen gas is added to propene with a catalyst?

  The double bond breaks and propane forms
• What is the product formed when propene reacts with hydrogen?

  Propane
• What conditions are required for the reaction of ethene with water?

  Catalyst and high temperatures
• What does the water molecule split into during the reaction with ethene?

  A hydrogen atom and an OH group
• What is the product formed when ethene reacts with water?

  Ethanol
• What type of compound is ethanol?

  Alcohol
• How is ethanol separated from unreacted ethene and water?

  By cooling and fractional distillation
• Why is ethene easy to separate from the mixture?

  It has a relatively low boiling point
• What happens to ethanol during fractional distillation?

  It evaporates first due to lower boiling point
• What happens when bromine is added to ethene?

  It forms dibromoethane and decolorizes
• How do alkenes differ from alkanes in terms of reactivity with bromine?

  Alkenes can decolorize bromine water
• What color does bromine water turn when reacting with alkenes?

  Colorless
• Why do alkanes not react with bromine water?

  They do not have double bonds
• What is the main test to distinguish alkenes from alkanes?

  • Adding bromine water
  • Alkenes decolorize bromine water
  • Alkanes do not react with bromine