C3H8, commonly known as propane, primarily exhibits London dispersion forces as its main type of intermolecular force. These forces arise due to instantaneous dipoles that occur when electrons move around the nucleus of an atom, creating temporary dipoles that can induce similar dipoles in neighboring molecules.
In the case of propane, being a nonpolar molecule, it lacks permanent dipoles, meaning that dipole-dipole interactions and hydrogen bonding are not applicable. The absence of these stronger interactions means that the London dispersion forces, although relatively weak compared to other types of intermolecular forces, are the predominant forces at play.
Overall, while propane may not have the strong intermolecular forces associated with polar molecules, the London dispersion forces are sufficient for maintaining the structure of propane in its gaseous state at room temperature and pressure.