C3H4; C2H6;
Thus, C2H6 (ethane) is a saturated hydrocarbon.
If the number of hydrogen atoms is 2 less than double the number of carbon atoms, then it will be an alkyne. The general formula of alkyne is CnH2n-2. Here, n is number of carbon atoms. Alkynes are unsaturated hydrocarbons.
Thus, C3H4 (Propyne) is an unsaturated hydrocarbon.