What is the IUPAC name for C2H6?

The molecular formula C2H6 corresponds to a hydrocarbon with two carbon atoms. According to IUPAC nomenclature, the naming of alkanes is based on the number of carbon atoms present in the molecule. The prefix for a two-carbon chain is "eth-," which designates it as an alkane. Since C2H6 has all single bonds connecting the carbon atoms, it is classified as an alkane, and thus its name is "ethane."

The structure of ethane consists of two carbon atoms bonded to each other, with each carbon fully saturated by hydrogen atoms (each carbon forms four bonds in total). This aligns with the general formula for alkanes, which is CnH2n+2. For n=2, this indeed results in C2H6.

The other choices represent different compounds: disilane signifies a compound with silicon, propane has three carbon atoms, and butene indicates a four-carbon alkene, which contains a double bond. None of these align with the molecular formula in question, confirming that "ethane" is the correct IUPAC name for C2H6.