Answer: C3H4 (Propayne) have a triple bond.
Step-by-step explanation:
The hydrocarbons which having triple bond are called alkyne. The general formula of alkyne is CnH2n-2. Here, n is number of carbon atoms.
In alkyne, the number of hydrogen atom is 2 less than double the number of carbon atoms.
Thus, the compound C3H4 (Propyne) have a triple bond.