Question

Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R).
Assertion (A) : A gas is confined by a piston at pressure '$P$' and the external pressure is $P_{ex}$. If the $P_{ex}$ is measurably greater than internal pressure, then decreasing $P_{ex}$ infinitesimally will not decrease it below the pressure of the gas and will not change the direction of the process.
Reason (R) : The system is in mechanical equilibrium with its surrounding and the compression is thermodynamically reversible.
In the light of the above statements, choose the most appropriate answer from the options given below :

• A. Both (A) and (R) are correct and (R) is the correct explanation of (A)
• B. Both (A) and (R) are correct but (R) is not the correct explanation of (A)
• C. (A) is correct but (R) is not correct
• D. (A) is not correct but (R) is correct

Hint:

Reversibility in thermodynamics implies that a process can be perfectly reversed by an infinitesimally small change in external conditions. If there's a macroscopic, measurable difference in forces or pressures, the process is spontaneous and irreversible.

Answer 1

The Correct Option is C