What is the IUPAC name for C3H8?

The IUPAC name for the molecular formula C3H8 is propane. In organic chemistry, hydrocarbons are classified according to the number of carbon atoms they contain. Propane is an alkane, which is a type of hydrocarbon characterized by single bonds between carbon atoms.

For C3H8, the formula can be broken down as follows: "C3" indicates that there are three carbon atoms, and "H8" signifies that there are eight hydrogen atoms. In alkanes, the general formula is CnH(2n + 2). Substituting n = 3 into this formula gives H(2*3 + 2) = H8, which matches the given formula. Thus, C3H8 conforms to the structure of propane, which features a straight-chain configuration of three carbon atoms with each carbon fully saturated with hydrogen atoms.

The other names correspond to alkanes with different numbers of carbon atoms: butane has four carbon atoms, pentane has five, and octane has eight, which is why they do not apply to the molecular formula C3H8.