Answer. The hydrocarbons in which two carbon atoms are linked by a double or a triple bond are called unsaturated hydrocarbons. The compounds in which two carbon atoms are linked by a double bond are called alkenes. For example, ethane and propene.
H2C=CH2 H3C-CH=CH2
Ethene Propene
These compounds have general formula CnH2n and functional group >C = C<.
The hydrocarbons in which two carbon atoms are linked by a triple bond are called alkynes. For example, ethyne and propyne.
HC≡CH H3C-O≡CH
Ethyne Propyne
They have general formula CnH2n-2 and functional group