What is the IUPAC name for C4H10?

The molecular formula C4H10 corresponds to butane, which is an alkane with four carbon atoms. According to the rules of IUPAC nomenclature, the name for an alkane is derived from the number of carbon atoms present in the longest continuous chain, with the suffix "-ane" indicating that it is a saturated hydrocarbon.

For C4H10, the structure consists of a straight chain of four carbon atoms (butane) or it can exist in a branched form known as isobutane. However, regardless of the structure, the molecular formula still identifies it as butane since there are four carbon atoms.

Other choices refer to alkanes with different numbers of carbon atoms. Octane is C8H18, nonane is C9H20, and decane is C10H22. Thus, those options do not match the formula C4H10 and are incorrect. Therefore, the IUPAC name for C4H10 is clearly butane.