A. Is zero
B. Increases
C. Decreases whereas the entropy increases
D. And entropy both decrease
✅ The correct answer is option C.
Thermodynamics MCQs
The third law of thermodynamics states that the
A. Heat capacity of a crystalline solid is zero at absolute zero temperature
B. Heat transfer from low temperature to high temperature source is not possible without external work
C. Gases having same reduced properties behave similarly
D. None of these
✅ The correct answer is option A.
The Carnot co-efficient of performance (COP) of a domestic air conditioner compared to a household refrigerator is
A. Less
B. More
C. Same
D. Dependent on climatic conditions
✅ The correct answer is option A.
When pressure is applied on the system, ice ⟷ water, then
A. Equilibrium can not be established
B. More ice will be formed
C. More water will be formed
D. Evaporation of water will take place
✅ The correct answer is option C.
Gibbs free energy of a pure fluid approaches __________ as the pressure tends to zero at constant temperature.
A. Infinity
B. Minus infinity
C. Zero
D. None of these
✅ The correct answer is option B.
The enthalpy change when ammonia gas is dissolved in water is called the heat of
A. Solution
B. Formation
C. Dilution
D. Combustion
✅ The correct answer is option A.
During a reversible isothermal expansion of an ideal gas, the entropy change is
A. +ve
B. 0
C. -ve
D. ∞
✅ The correct answer is option A.
At equilibrium condition, the chemical potential of a material in different phases in contact with each other is equal. The chemical potential for a real gas (μ) is given by(where, μ = standard chemical potential at unit fugacity (f° = 1 atm.) and the gas behaves ideally.)
A. μ° + RT ln f
B. μ°+ R lnf
C. μ° + T lnf
D. μ° + R/T lnf
✅ The correct answer is option A.
Entropy change for an irreversible process taking system and surrounding together is
A. 0
B. > 0
C. < 0
D. None of these
✅ The correct answer is option B.
PVy = constant, holds good for an isentropic process, which is
A. Reversible and isothermal
B. Isothermal and irreversible
C. Reversible and adiabatic
D. Adiabatic and irreversible
✅ The correct answer is option C.