Chemistry Form 5: Chapter 2 - Differences between Alkanes and Alkenes

	Alkanes	Alkenes
General formula	CHnH2n+2	CHnH2n
Naming	All the members end with 'ane'	All the members end with 'ene’
Physical state	Members having 1-4 carbon atoms per molecule are gases/5-17 carbon atoms are liquids and 18 or more are solids at room temperature	Members having 2-4 carbon atoms per molecule are gases/5-15 carbon atoms per molecule are liquids and the higher members are solids
Melting and boiling points	The melting and boiling points increases with increase in molecular mass.	The melting and boiling points increases with the increase in molecular mass
Solubility	They are insoluble in water; soluble in benzene, alcohol, ether and carbon tetrachloride.	They are insoluble in water; soluble in benzene, ethanol and ether.
Combustion	They undergo complete combustion production CO2 , H2O and heat.	They burn with a sooty flame because of the higher percentage of carbon in them producing CO2 , H2O and heat.
Substitution reaction	Undergo substitution substitution reaction in the presence of sun light	Do not undergo substitution reaction.
Addition reaction	Do not undergo addition reaction as they are saturated	Undergo addition reactions
Reaction with bromine water	Do not decolorise bromine water	Decolorise bromine water
Reaction with acidified KMnO4	Do not decolorise acidified KMnO4 solution	Decolorise acidified KMnO4 solution
	Saturated Hydrocarbon	Unsaturated Hydrocarbon

Bromine Test

Acidified Potassium Manganate (VII) solution Test


Combustion of alkene produces more soot than alkane