Nitrogen has a lower boiling point than oxygen because of its weaker intermolecular forces. Nitrogen molecules are nonpolar and have only weak van der Waals forces between them. Oxygen molecules, on the other hand, are polar and have stronger hydrogen bonds between them. The stronger hydrogen bonds in oxygen require more energy to break, which is why oxygen has a higher boiling point.

The number of covalent bonds in a molecule does not directly affect its boiling point. Boiling point is determined by the strength of the intermolecular forces between molecules, not the strength of the covalent bonds within molecules.