211. A system is said to be at equilibrium, if the entropy of the system has reached __________ value.
A. Minimum
B. Zero
C. Maximum
D. None of these
✅ The correct answer is option C.
Thermodynamics MCQs
212. Joule-Thomson co-efficient for a perfect gas is
A. Zero
B. Positive
C. Negative
D. None of these
✅ The correct answer is option A.
213. Specific/molar Gibbs free energy for a pure substance does not change during
A. Sublimation
B. Vaporisation
C. Melting
D. Either A, B or C
✅ The correct answer is option D.
214. Joule-Thomson Co-efficient at any point on the inversion curve is
A. ∞
B. + ve
C. 0
D. -ve
✅ The correct answer is option C.
215. As pressure approaches zero, the ratio of fugacity to pressure (f/P) for a gas approaches
A. Zero
B. Unity
C. Infinity
D. An indeterminate value
✅ The correct answer is option B.
216. __________ does not change during phase transformation processes like sublimation, melting & vaporisation.
A. Entropy
B. Gibbs free energy
C. Internal energy
D. All of the above
✅ The correct answer is option B.
217. Heat of formation of an element in its standard state is
A. 0
B. < 0
C. > 0
D. A function of pressure
✅ The correct answer is option A.
218. Specific __________ does not change during phase change at constant temperature and pressure.
A. Entropy
B. Gibbs energy
C. Internal energy
D. Enthalpy
✅ The correct answer is option B.
219. Filling of gas from a high pressure cylinder into small bottles is an example of a/an __________ process.
A. Equilibrium
B. Adiabatic
C. Steady
D. Unsteady
✅ The correct answer is option D.
220. Free energy
A. Decreases in all spontaneous (or irreversible) processes
B. Change during a spontaneous process has a negative value
C. Remains unchanged in reversible processes carried at constant temperature and pressure
D. All of the above
✅ The correct answer is option D.