Question

Which of the following factors are responsible for origination of van der Waals forces?

• A. Instantaneous dipole-induced dipole interaction.
• B. Dipole-induced dipole interaction and ion-induced dipole interaciton.
• C. Dipole-dipole interaction and ion-induced dipole interaction.
• D. Small size of molecule.

Answer 1

Answer: (A), (B), (C)

The correct options are
A Dipole-induced dipole interaction and ion-induced dipole interaciton.
B Instantaneous dipole-induced dipole interaction.
C Dipole-dipole interaction and ion-induced dipole interaction.

$VanderWaal$ forces are originated by all the stated factors except small size of molecule.

$VanderWaal$ forces are result of electrostatic attractions between temporary dipoles caused by movement of electrons in atoms and molecules .

They are significant only in atoms or molecules which have no other type of inter molecular forms of attraction, for eg. discrete non polar molecules and the group 0 elements.

The strength of $VanderWaals$ is related to the size of atoms and molecules. The bigger the atom/molecule, the bigger the $VanDerWaals$ force.

Hence options A,B and C are correct.