In terms of thermodynamics, when molecules of substance have enough energy to overcome intermolecular forces, they get miscible with each other. In case of intermolecular force, when molecules have enough energy to approach atom of other molecule Solution In terms of thermodynamics, when molecules of substance have enough energy to overcome intermolecular forces, they get miscible with each other. In case of intermolecular force, when molecules have enough energy to approach atom of other molecule.