1. H₂S and H₂Se exhibit the following intermolecular forces dipole-dipole forces and dispersion forces. Hence, both the molecule possess certain dipole moment and they interact with each other. The dispersion force is also known as London force, and this is the weakest intermolecular force.
2. Therefore, when comparing H₂S and H₂Se, the one with a higher molar mass has a higher boiling point. As one knows that high molecular mass means that more energy is needed.
3. The strongest intermolecular force exhibited by H₂O is hydrogen bonding.
4. Therefore, when comparing H₂Se and H₂O, the one with stronger intermolecular forces has a higher boiling point.
