Why does a gas exert pressure?

Hint: The intermolecular attraction between the particles is directly proportional to how loosely packed the molecule is. The more loosely packed the molecule is, the more is the movement of the particles. Due to this movement of particles, the pressure is exerted. Gases have less intermolecular attraction between the particles and the movement of particles is random in all directions. Use this basic information to find why gas exerts pressure.

Complete step-by-step solution:
The intermolecular attraction between the particles of a gas molecule is very small and thus, the intermolecular spacing between them is very large. So, the particles move in all directions randomly. Due to weaker intermolecular attraction between the particles, they keep colliding with each other and also with the wall of the container exerting force and pressure. This changes the direction of the motion of the molecule. In return, the molecules also exert pressure on the wall. The more particles hit the container, the more force will be exerted. Hence, more pressure will be exerted.
The pressure of any gas can be calculated using the formula given by,
$PV=nRT$
Where P is the pressure exerted on the gas
             V is the volume of the container
             n is the amount of gas
             R is the constant
             T is the temperature in Kelvin
Hence, gas exerts pressure.

Note: Pressure exerted by the gas can be increased in different ways which are as follows:
1. By increasing temperature.
2. By increasing the amount of gas.
3. By decreasing the volume of the container.
A gas exerts more pressure on the wall of the container as compared to solid and liquid because of less intermolecular attraction between the particles of gas.