Which of the following alkanes has the molecular formula C4H10?

Butane is the alkane that has the molecular formula C4H10. This formula indicates that it consists of four carbon atoms and ten hydrogen atoms. In alkanes, the general molecular formula is CnH2n+2, where n represents the number of carbon atoms. For butane, substituting n with 4 gives us:

C4H(2(4)+2) = C4H10.

Butane exists in two structural forms: n-butane and isobutane (or methylpropane), but both conform to the same molecular formula, C4H10.

The other options do not fit this formula. Propane has three carbon atoms (C3H8), ethane contains two carbon atoms (C2H6), and pentane includes five carbon atoms (C5H12). Thus, the only alkane that correctly corresponds to the molecular formula C4H10 is butane.