The number of carbon atoms in the molecule of this hydrocarbon is 3, that is , n =3
(i) The general foumula of an alkane is `C_(n)H_(2n+2)` where n is the number of carbon atoms in one molecule of the alkane. Here , n =3 so putting n=3 in this general foumula we get `C_(3)H_(2xx3+2) or C_(3)H_(8)` .Thus the molecular formula of hte given hydrocarbon if it is an alkane is `C_(3)H_(8)`. please solve the remaining two parts of this problem yourself . The answers wil be `C_(3)H_(6)` for alkene and `C_(3)H_(4)` for alkyne.