Hydrogen chloride (HCl) exhibits dipole-dipole interactions as its primary intermolecular force. Since HCl is a polar molecule, with the chlorine atom being more electronegative than the hydrogen atom, it creates a permanent dipole. This means that the chlorine end of the molecule has a partial negative charge, while the hydrogen end has a partial positive charge.
When HCl molecules come close to each other, the positive end of one molecule is attracted to the negative end of another molecule. This attraction between the opposite charges is known as a dipole-dipole interaction. These forces are stronger than London dispersion forces but weaker than hydrogen bonds.
In addition to dipole-dipole interactions, HCl also experiences London dispersion forces. These are weak intermolecular forces that occur due to temporary dipoles induced in atoms or molecules. However, in the case of HCl, the dipole-dipole interactions are more significant due to the molecule’s polarity.