Which of the following compounds has the molecular formula C3H8?

The molecular formula C3H8 corresponds specifically to the compound known as propane. Propane is an alkane, which is a saturated hydrocarbon, meaning that it contains only single bonds between carbon atoms. In propane, there are three carbon (C) atoms and eight hydrogen (H) atoms, which fits the formula perfectly.

To further understand why propane is the correct identification, consider how the other options relate to their molecular formulas.

Butane has four carbon atoms, represented by the formula C4H10, which indicates it cannot match the molecular formula C3H8. Similarly, pentane has five carbon atoms with the formula C5H12, and hexane contains six carbon atoms with the formula C6H14. Each of these compounds has more carbon atoms than found in propane, thus they cannot be represented by the formula C3H8.

This illustrates that propane is the only compound provided that accurately corresponds to the molecular formula C3H8.