How is \[W = PV\] ?

Hint: To solve this question, we must have the concept related to thermodynamic processes. In this topic we must know about Work in Thermodynamic Processes. A thermodynamic system is a distinct area or macroscopic region in the universe in which one or more thermodynamic processes occur and whose state may be represented in terms of pressure, temperature, and volume. Anything outside of this thermodynamic system is referred to as the environment, and is separated from it by a border. The universe is made up of the surroundings, system, and boundaries.

Complete step by step answer:
It is said that pressure-volume work happens when the volume (V) of a system changes. A quasi-static process is a thermodynamic process that occurs in a closed system where the rate of volume change is slow enough for the pressure (P) to remain constant and uniform throughout the system. Work (W) is expressed in this situation as:
\[\delta W = PdV\]
Where we can say that, $\delta W$ is the infinitesimal work increment by the system and $dV$ is the infinitesimal volume increment.
Also, $W = \int {PdV} $
Where, $W$ is the work, in which the system does during the complete reversible process.

Note: For an isobaric process the pressure is constant in this process, and the volume of the system keeps changing. So, the work done can be calculated as $W = P({V_{final}} - {V_{initial}})$. It's also known as the energy conservation law. This law states that energy cannot be generated or destroyed, but can only be transformed from one form to another.The equation $Q = U + W$ is used to express it. When a system is supplied with a certain quantity of heat, a portion of it is utilised to increase the system's internal energy and the rest is used to do work.