Final answer:
HF exhibits stronger intermolecular forces than HI due to its ability to form strong hydrogen bonds, which are more potent than the London dispersion forces and weaker dipole-dipole interactions present in HI.
Step-by-step explanation:
Among the molecules HF and HI, HF exhibits stronger intermolecular forces of attraction. This is primarily because it is capable of hydrogen bonding, which is a powerful type of dipole-dipole interaction that occurs when a hydrogen atom is bonded to a very electronegative atom such as fluorine. The electronegative fluorine atom attracts the electron density from the hydrogen, creating a large dipole in the HF molecule. This allows HF molecules to form very strong hydrogen bonds with each other, leading to higher boiling points and stronger intermolecular forces than those found in HI, which can only exhibit weaker London dispersion forces.
In contrast, hydrogen iodide (HI) is a larger molecule with more electrons and thus has larger London dispersion forces than a small molecule like F2, but these are still substantially weaker than the hydrogen bonds in HF. While HI does have dipole-dipole interactions due to its polar nature, these are significantly weaker compared to the hydrogen bonds in HF. Therefore, HF has the stronger intermolecular forces between the two molecules.