Introduction:
Gas and liquid are two states of matter with different properties. One of the key differences between them is their compressibility. While gases are highly compressible, liquids are considered to be nearly incompressible. This can be explained by understanding the behavior of particles and the intermolecular forces within each state.

Behavior of particles in gases and liquids:
In a gas, the particles are in constant motion and have large distances between them. They move freely and rapidly, colliding with each other and with the walls of the container. The particles in a liquid are also in motion but are much closer together compared to gases. They have weaker intermolecular forces and are more attracted to each other than gas particles.

Intermolecular forces:
Intermolecular forces are the attractive forces between molecules or atoms in a substance. These forces play a crucial role in determining the compressibility of a substance. In gases, the intermolecular forces are relatively weak, allowing the gas particles to move more freely and occupy a larger volume. Liquids, on the other hand, have stronger intermolecular forces, which tend to hold the particles close together.

Compressibility of gases:
Gases are compressible because of the large distances between their particles and the weak intermolecular forces. When pressure is applied to a gas, the particles can be easily pushed closer together, reducing the volume occupied by the gas. This is because the gas particles have enough space to move and rearrange themselves in response to external pressure.

Incompressibility of liquids:
Liquids are nearly incompressible due to their closer particle arrangement and stronger intermolecular forces. When pressure is applied to a liquid, the particles are already close together, and there is limited space for them to move and rearrange themselves. As a result, the volume occupied by the liquid does not change significantly when pressure is applied.

Summary:
In summary, the compressibility of gases and the incompressibility of liquids can be attributed to the behavior of particles and the strength of intermolecular forces. Gases have greater distances between particles and weaker intermolecular forces, allowing them to be easily compressed. Liquids, however, have closer particle arrangement and stronger intermolecular forces, making them nearly incompressible.