Reactions of Alkenes Flashcards
What are the types of reactions for alkenes? (2)
Combustion
Addition
The combustion of alkenes is an ___ process.
Exothermic
What are the four types of addition reactions for alkenes?
- Addition of hydrogen
- Addition of water
- Addition of halogen
- Addition of H-X (hydrogen-halide)
What do we call the addition of hydrogen?
Hydrogenation
What happens during a hydrogen addition reaction?
This reaction converts an alkene into an alkane. The reaction needs a catalyst-typically platinum (nickel and palladium as well).
What do we call the addition of water?
Hydration
What happens during a water addition reaction?
The addition of water (steam) is usually carried out in the presence of H2SO4 or H3PO4 catalyst. The alkene is converted into an alcohol.
What do we call the addition of a hydrogen-halide?
Hydrohalogenation
What happens during a halogen-halide addition reaction?
The addition of a hydrogen-halide produces a halo-alkane. This reaction doesn’t need a catalyst.
What do we call the addition of a halogen?
Halogenation
What happens during a halogen addition reaction?
This is a fast reaction which forms the dihalo-alkane.
What is the addition of Bromine to an alkene used for?
It is used to test for unsaturation. The brown bromine goes colourless in the presence of U.V. Light.
No U.V. Light
Alkane –> _______
Alkene –> _______
Stays brown
Brown colour goes colourless
U.V. Light Present
Alkane–> (slow) _____
Alkene –> (fast) _____
Brown colour goes colours for both reactions
