The correct statements (s) about intermolecular forces is(are)
- (A)The potential energy between two point charges approaches zero more rapidly than the potential energy between a point dipole and a point charge as the distance between them approaches infinity.
- (B)The average potential energy of two rotating polar molecules that are separated by a distance r has dependence.
- (C)The dipole-induced dipole average interaction energy is independent of temperature.✓ Correct
- (D)Nonpolar molecules attract one another even though neither has a permanent dipole moment.✓ Correct
Answer: (C), (D)
Solution
(A) is incorrect: Ion-ion interaction energy ∝ 1/r, while ion-dipole interaction energy ∝ 1/r². As r → ∞, the ion-dipole interaction (1/r²) approaches zero MORE rapidly than ion-ion (1/r).
(B) is incorrect: For two rotating polar molecules (dipole-dipole interaction), the average interaction energy ∝ 1/r⁶, not 1/r³.
(C) is correct: Dipole-induced dipole forces arise from the polarization of a nonpolar molecule by a polar one. This interaction energy is independent of temperature because it doesn't involve thermal averaging of dipole orientations.
(D) is correct: Nonpolar molecules exhibit London dispersion forces (instantaneous dipole-induced dipole interactions), which cause attraction even in the absence of permanent dipoles.
(B) is incorrect: For two rotating polar molecules (dipole-dipole interaction), the average interaction energy ∝ 1/r⁶, not 1/r³.
(C) is correct: Dipole-induced dipole forces arise from the polarization of a nonpolar molecule by a polar one. This interaction energy is independent of temperature because it doesn't involve thermal averaging of dipole orientations.
(D) is correct: Nonpolar molecules exhibit London dispersion forces (instantaneous dipole-induced dipole interactions), which cause attraction even in the absence of permanent dipoles.
JEE Advanced · 2025 · 18 May 2025 · Paper 2 · One or more correct options