Question

What is meant by intermolecular interaction? What is its role in the states of matter?

Answer 1

To answer this question, we first need to understand what a molecule is. A molecule is a collection of two or more atoms that make up the smallest identifiable unit into which a pure material can be divided while maintaining its makeup and chemical properties.

Complete answer: Intermolecular forces -
Intermolecular forces are forces of attraction or repulsion that act between atoms and other types of nearby particles, such as atoms or ions, to mediate interaction between molecules. In comparison to intramolecular forces, which hold a molecule together, intermolecular forces are weak.
For example, the covalent connection, which involves atoms sharing electron pairs, is substantially stronger than the forces that exist between molecules. Both types of forces are important components of force fields in molecular mechanics.
The study of intermolecular forces begins with macroscopic measurements that show the presence and activity of forces at the molecular level. Virial coefficients, vapor pressure, viscosity, surface tension, and absorption data are examples of non-ideal-gas thermodynamic behavior.
Role in the states of matter –
-Dispersion in London All atoms and molecules are attracted to each other by forces.
-Uneven electron distribution can cause temporary dipoles in particles. These transient dipoles are attracted to one another. The strongest of these forces can be found in big, polarizable molecules.
-The attraction between the positive and negative ends of molecules having permanent dipoles causes dipole forces. Polar molecules exhibit stronger intermolecular forces than nonpolar molecules of comparable size and polarity because dipoles are stronger than London Forces alone.
-A hydrogen atom is covalently bonded to a strongly electronegative atom (N, O, F), resulting in a huge dipole. Even tiny molecules have strong intermolecular bonds as a result of this.
Coulombic interactions between positively and negatively charged ions are known as ionic interactions. -Ionic materials (such as table salt, NaCl) are solids because they are usually quite strong. In solution, ions can generate strong interactions with the dipoles of solvents. Ionic solids dissolve in polar solvents like water because of this. The types of intermolecular interactions in a substance determine properties such as boiling temperature, vapor pressure, and solubility in polar or nonpolar solvents.

Note:
The balance between intermolecular interactions and the thermal energy of the molecules produces three states of matter. When molecular interactions are weak, molecules do not stick together to form a liquid or solid until the temperature is lowered to minimize thermal energy.