Give the types of van der Waals forces and explain any one.

(N/A) The van der Waals forces are primarily categorized into the following types:
$1$. London dispersion forces
$2$. Dipole-dipole forces
$3$. Dipole-induced dipole forces
Explanation of Dipole-Dipole forces:
Dipole-dipole forces act between molecules possessing a permanent dipole. For example,$HCl$,$HF$,$CO$,$NO$,and $NH_{3}$ exhibit these forces.
The ends of the dipoles possess "partial charges" denoted by the Greek letter delta $(\delta)$. These partial charges are always less than the unit electronic charge $(1.6 \times 10^{-19} \ C)$.
Formation: Neighbouring polar molecules interact with each other. Figure $(a)$ shows the electron cloud distribution in a hydrogen chloride dipole,and Figure $(b)$ shows the dipole-dipole interaction between two $HCl$ molecules.
Characteristics:
- This interaction is stronger than London forces but weaker than ion-ion interaction because only partial charges are involved.
- The attractive force decreases as the distance between the dipoles increases.
- The interaction energy is inversely proportional to the distance between polar molecules.
- Dipole-dipole interaction energy between stationary polar molecules (as in solids) is proportional to $1/r^{3}$,and for rotating polar molecules,it is proportional to $1/r^{6}$,where $r$ is the distance between molecules.
- Note: Polar molecules also exhibit London forces; thus,the total intermolecular force is the sum of dipole-dipole and London forces:
$\text{Total attraction} = \text{Dipole-Dipole attraction} + \text{London attraction forces}$