Which orbital is non directional?
They are non directional because they are spherical in shape and probability of finding electrons at a particular distance from the nucleus is same in all directions.
What is van der waal's forces(intermolecular forces). And what is van der waal's bond?
Intermolecular forces, often abbreviated to IMF, are the attractive and repulsive forces that arise between the molecules of a substance. These forces mediate the interactions between individual molecules of a substance.
Van der Waals bond is weak intermolecular forces that are dependent on the distance between atoms or molecules.
It is the attraction between instantaneous dipole and induced dipole.