∙ Alkane containing 3 carbon atoms:
With n=3, the molecular formula of an alkane is C3H8.
The condensed structural formula is CH3CH2CH3.
Therefore, the IUPAC name is propane.
∙ Alkene containing 3 carbon atoms:
With n=3, the molecular formula of an alkene is C3H6.
The condensed structural formula is CH3CH=CH2.
Therefore, the IUPAC name is propene or prop-1-ene.
∙ Alkyne containing 3 carbon atoms:
With n=3, the molecular formula of an alkyne is C3H4.
The condensed structural formula is CH3C≡CH.
Therefore, the IUPAC name is propyne or prop-1-yne.