For the isothermal expansion of an ideal gas in a piston cylinder system, the net heat supplied during the process is equal to the net work done. Which of the following statement is correct for the given process?

The correct option is: The process is possible

Let us analyze why this statement is correct by applying the laws of thermodynamics to the given process.

First, we consider the First Law of Thermodynamics for a closed system (such as a gas in a piston-cylinder system undergoing a process):

$Q=\mathrm{\Delta }U+W$

where:
- $Q$ is the net heat supplied to the system,
- $\mathrm{\Delta }U$ is the change in internal energy of the system, and
- $W$ is the net work done by the system.

For an ideal gas, internal energy $U$ is a function of temperature only ($U=f\left(T\right)$). Since the expansion is isothermal, the temperature remains constant ($\mathrm{\Delta }T=0$). Consequently, there is no change in internal energy during the process:

$\mathrm{\Delta }U=0$

Substituting this back into the first law equation gives:

$Q=W$

This shows that the first law of thermodynamics is fully satisfied, as the net heat supplied is exactly equal to the net work done.

Now, let us examine if this process violates the Second Law of Thermodynamics. The Kelvin-Planck statement of the second law states that it is impossible for any device that operates on a thermodynamic cycle to receive heat from a single reservoir and produce a net amount of work. However, the process described here is a single process (isothermal expansion in a piston-cylinder device) and not a thermodynamic cycle. The Kelvin-Planck restriction does not apply to individual, non-cyclic processes. Therefore, converting all supplied heat into work during a single expansion process does not violate the second law.

Since the process does not violate either the first or the second law of thermodynamics, the process is completely possible and physically realizable.