Saturated hydrocarbons: In this type of hydrocarbons, the carbon atoms are connected by a single covalent bond. These are called alkane and general formula CnH2n+2 where n=1,2,3….etc. These are less reactive as they contain strong sigma bond. They do not undergo hydrogenation reaction. For example: CH4.Unsaturated hydrocarbons: In this type of hydrocarbons, the carbon atoms are connected by multiple bonds like double or triple bonds. The double bonded compounds are called alkene and has general formula CnH2n and triple bonded compounds are called alkynes and has general formula CnH2n-2. These are more reactive as they contain one or more pi bonds which can be easily broken. They can undergo hydrogenation reaction. For example: CH2=CH2 is an alkene.
Single Bond present between hydrogen and carbon is called saturated hydrocarbon and more than one is known as unsaturated