Intermolecular Forces

Let’s examine each statement individually: (A) Incorrect - For two point charges, the potential energy falls off as . - For a point dipole and point charge, the interaction energy falls off as . - Hence, the potential between two point charges decreases more slowly (not rapidly) compared to that between a point dipole and a charge. (B) Incorrect - For two rotating polar molecules, the orientation averages out due to thermal motion. - The correct dependence for such interactions (Keesom interaction) is: - Statement says which applies to aligned, non-rotating dipoles. (C) Correct - Dipole–induced dipole interaction (Debye interaction) does not depend on thermal averaging. - It is due to a permanent dipole inducing a dipole in a non-polar molecule, and this interaction is independent of temperature. (D) Correct - Even nonpolar molecules attract each other via London dispersion forces (instantaneous dipole-induced dipole). - These are weak Van der Waals forces but always present, especially significant in noble gases.