Final answer:
Acetylene, with the formula C2H2, correctly has one triple bond between the carbon atoms, making it an alkyne.
Step-by-step explanation:
The correct description for acetylene, which has the formula C2H2, is that it has one triple bond between the two carbon atoms. Acetylene, also known as ethyne, belongs to a class of compounds called alkynes which are characterized by the presence of a carbon-to-carbon triple bond. This triple bond consists of one sigma (σ) bond and two pi (π) bonds, which is indicated by the formula H-C≡C-H. The carbon atoms in acetylene make four total bonds, two of which are with hydrogen atoms and the remaining two (triple bond) between each other.