- A homologous series of hydrocarbons that contains only single carbon bonds.
- Since alkanes contain only single carbon bonds, they are saturated hydrocarbons.
- The general formula for alkanes are CnH2n+2, where n is the number of carbons in the alkane.
Butane and pentane have isomers: Isomers are compounds that have the same molecular formula but have different structures.
Reaction of alkanes with halogens:
- Substitution reaction is a reaction in which one atom is swapped with another atom.
- In the presence of UV light, alkanes undergo a substitution reaction with halogens.
- A homologous series of hydrocarbons that contains double carbon bonds.
- Since alkenes contain double carbon bonds, they are unsaturated hydrocarbons.
- The general formula for alkenes are CnH2n, where n is the number of carbons in the alkene.
Butene has two isomers based on the location of the carbon double bond.
Reaction of alkenes with bromine:
- Alkenes undergo an addition reaction with bromine.
- Diatomic bromine is added across the carbon double bond of the alkene.
Using Bromine Water to Distinguish Alkanes and Alkenes
- Bromine water is an orange-coloured solution of bromine.
- When bromine water is shaken with an alkane, there is no change.
- When bromine water is shaken with an alkene, bromine water becomes decolourised as the addition reaction to the double carbon bond results in the formation of a colourless dibromoalkane.