Final answer:
Both HCl and HBr exhibit dipole-dipole attractions, but HCl likely exhibits stronger attractions due to chlorine's higher electronegativity compared to bromine.
Step-by-step explanation:
In the comparison between HCl (hydrogen chloride) and HBr (hydrogen bromide), both molecules exhibit dipole-dipole attractions. This is because both are polar molecules, with a partial positive charge on the hydrogen atom and a partial negative charge on the halogen atom.
However, the strength of this attraction is typically stronger in HCl due to chlorine being more electronegative than bromine, which creates a greater polarity within the molecule. Electronegativity differences between the atoms in a molecule are what lead to the development of a dipole, with the more electronegative atom acquiring a partial negative charge. As a result, HCl molecules would exhibit a slightly stronger dipole-dipole attraction compared to HBr molecules because of the higher electronegativity of chlorine.