(a) Ethyne is a highly reactive compound than ethene because of the presence of a triple bond between its two carbon atoms.
(b) Ethene is a highly reactive compound than ethane because of the presence of a double bond between its two carbon atoms.
(c) Hydrocarbons such as alkanes undergo combustion reactions with oxygen to produce carbon dioxide and water vapor. Alkanes are flammable which makes them excellent fuels.
Methane, for example, is the principal component of natural gas.
CH 4 + 2O2 → CO2 + 2H2O