Pick out the wrong statement.

A. The values of $${\left( {\frac{{\partial {\text{P}}}}{{\partial {\text{V}}}}} \right)_{\text{T}}}$$  and $${\left( {\frac{{{\partial ^2}{\text{P}}}}{{\partial {{\text{V}}^2}}}} \right)_{\text{T}}}$$  are zero for a real gas at its critical point

B. Heat transferred is equal to the change in the enthalpy of the system, for a constant pressure, non-flow, mechanically reversible process

C. Thermal efficiency of a Carnot engine depends upon the properties of the working fluid besides the source & sink temperatures

D. During a reversible adiabatic process, the entropy of a substance remains constant

Answer: Option C

Solution(By Examveda Team)

We know from second law of thermodynamics that all the reversible engines working under the same temperature reservoirs have same efficiency. Since Carnot engine is an reversible engine. So, the efficiency of a Carnot engine doesn’t depends upon the working fluid involved. It just depends upon the temperatures of then reservoirs involved.