Alkanes are acyclic hydrocarbons in which carbon-carbon atoms have a single bond between them, i.e. they are saturated hydrocarbons.
The general formula for alkanes is CnH2n+2 , where 'n' is the number of carbon atoms.
Propane is the third member of the alkane family with 3 carbon atom. If we put the number of carbon and hydrogen atoms present in propane in the above-mentioned formula, we will find that it holds true.
CH4 is Methane, the first member of the alkane family.
C4H10 is Butane, the fourth in the line of alkanes.
C2H6 is Ethane, the second member of the alkane family.
The lower alkanes from C1toC4 are gases, from C5toC16 are liquids and beyond that are solids.