What is the difference between an alkane, an alkene, and an alkyne?
The most obvious one would be the number of carbon-carbon bonds between 2 carbon atoms.
Alkane = one C-C single bond between two carbon atoms; no pi bond.
Alkene = one C-C double bonds between two carbon atoms; one pi bond.
Alkyne = one C-C triple bond between two carbon atoms; two pi bonds.
The more pi bonds there are, the harder you can break it. Hence, the boiling point of alkynes are, higher than alkanes.