Alkanes

Alkenes

• Low reactivity.
• free-radical substitution reactions  involving photochemical homolytic fission.
• Free radicals should be represented by a single dot.

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• More reactive than alkane
• Hydrogenation = add H
• Halogenation = add halogen
• Hydrogen halides addition = add HCl... (reactivity order is HI>HBr>HCl due to the decreasing strength of the hydrogen halide bond down the group)
• Hydration = add water

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No reaction with bromine water

Bromine water can be used to distinguish between alkenes and alkanes.

Alkenes react with Br and bromine water turn clear. This is called test for unsaturation.

Writing equations for the complete and incomplete combustion of hydrocarbons:

• Complete make CO₂ + H₂O
• Incomplete make CO (carbon monoxide) and H₂O

Writing equations for the reactions of alkenes with hydrogen and halogens and of symmetrical alkenes with hydrogen halides and water.

Do not form polymer

The addition polymerization of alkenes

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