What is the IUPAC name for the simplest alkyne, C2H2?

The simplest alkyne, C2H2, is named ethyne in IUPAC nomenclature. The fundamental characteristic of alkynes is the presence of at least one carbon-carbon triple bond. In the case of ethyne, there are two carbon atoms each bonded with a triple bond, fulfilling the definition of an alkyne.

The name "ethyne" is derived from "eth-" which indicates the presence of two carbon atoms in the longest continuous chain, and the suffix "-yne" signifies that there's a triple bond present. This systematic naming convention aligns with the standard IUPAC rules, which help clearly identify the structure and bonding of the molecule.

Other potential names do not correspond to the structure of C2H2. For instance, butyne refers to a four-carbon alkyne, while propyne refers to a three-carbon alkyne, both of which have different numbers of carbon atoms than C2H2. Allene, on the other hand, typically has two double bonds and is not classified as an alkyne. Hence, ethyne is the correct IUPAC name for the simplest alkyne.