What is the IUPAC name for C5H12?

The molecular formula C5H12 corresponds to an alkane with a straight-chain structure consisting of five carbon atoms. In IUPAC nomenclature, alkanes are named based on the number of carbon atoms present in the longest continuous chain, with each carbon fully saturated by hydrogen atoms.

Given that C5H12 has five carbons, according to the IUPAC naming conventions, it is designated as pentane. The prefix "pent-" indicates that there are five carbon atoms, and adding the suffix "-ane" signifies that it is an alkane, which is characterized by single bonds only.

The other options represent alkanes with different numbers of carbon atoms. Hexane, for example, corresponds to C6H14 and has six carbon atoms, while octane has eight carbon atoms (C8H18), and heptane has seven carbon atoms (C7H16). Therefore, they do not fit the molecular formula C5H12, confirming that the correct name is indeed pentane.