481. Refrigerants commonly used for domestic refrigerators are
A. Ethyl chloride or methyle chloride
B. Freon-12
C. Propane
D. NH₃ or CO₂
✅ The correct answer is option A.
Thermodynamics MCQs
482. The necessary and sufficient condition for equilibrium between two phases is
A. The concentration of each component should be same in the two phases
B. The temperature of each phase should be same
C. The pressure should be same in the two phases
D. The chemical potential of each component should be same in the two phases
✅ The correct answer is option D.
483. Entropy is a measure of the __________ of a system.
A. Disorder
B. Orderly behaviour
C. Temperature changes only
D. None of these
✅ The correct answer is option A.
484. Heat of reaction at constant volume is identified with __________ change.
A. Enthalpy
B. Internal energy
C. Either A or B
D. Neither A nor B
✅ The correct answer is option B.
485. The minimum number of phases that can exist in a system is
A. 0
B. 1
C. 2
D. 3
✅ The correct answer is option B.
486. The temperature at which a real gas obeys the ideal gas laws over a wide range of pressure is called the __________ temperature.
A. Critical
B. Boyle
C. Inversion
D. Reduced
✅ The correct answer is option B.
487. Joule-Thomson experiment is
A. Isobaric
B. Adiabatic
C. Isenthalpic
D. Both B & C
✅ The correct answer is option D.
488. Which of the following is a thermodynamic property of a system?
A. Concentration
B. Mass
C. Temperature
D. Entropy
✅ The correct answer is option D.
489. Cp of a gas at its critical temperature and pressure
A. Becomes zero
B. Becomes infinity
C. Equals 1 kcal/kmol °K
D. Equals 0.24 kcal/kmol °K
✅ The correct answer is option B.
490. On opening the door of an operating refrigerator kept in a closed room, the temperature of the room will
A. Increase
B. Decrease
C. Remain same
D. Increase in summer and will decrease in winter
✅ The correct answer is option A.