Final answer:
Chloroacetylene is commonly known as C2HCl, distinguishing it from ethyne or acetylene (C2H2) which doesn't have a chlorine atom.
Step-by-step explanation:
The compound commonly known as chloroacetylene is C2HCl. This compound is part of the alkyne series of organic compounds which have a triple bond between carbon atoms. Chloroacetylene refers specifically to the compound where there is also a chlorine atom attached to one of these carbons. In contrast, the simplest member of the alkyne series without any halogen substitution is ethyne, C2H2, which is commonly called acetylene and has its structure represented by two carbon atoms triple-bonded together with a single hydrogen attached to each carbon.