1000+ Chemical Engineering Thermodynamics MCQ for IBPS SO [Solved]

1. In Joule-Thomson porous plug experiment, the
A. Enthalpy does not remain constant
B. Entire apparatus is exposed to surroundings
C. Temperature remains constant
D. None of these
Answer : D

2. Specific __________ does not change during a phase change (e.g. sublimation, melting, vaporisation etc.).
A. Entropy
B. Internal energy
C. Enthalpy
D. Gibbs free energy
Answer : D

3. Enthalpy 'H' is defined as
A. H = E - PV
B. H = F - TS
C. H - E = PV
D. None of these
Answer : C

4. Consider the reaction, C + O₂ ? CO₂; ?H = - 94 kcal. What will be the value of ?H for the reaction CO₂ ? C + O₂?
A. -94 kcal
B. +94 kcal
C. > 94 kcal
D. < -94 kcal
Answer : B

5. As the time is passing, entropy of the universe
A. Is increasing
B. Is decreasing
C. Remain constant
D. Data insufficient, can't be predicted
Answer : A

6. The standard state of a gas (at a given temperature) is the state in which fugacity is equal to
A. Unity
B. Activity
C. Both (A) & (B)
D. Neither (A) nor (B)
Answer : C

7. __________ decreases during adiabatic throttling of a perfect gas.
A. Entropy
B. Temperature
C. Enthalpy
D. Pressure
Answer : D

8. At the absolute zero temperature, the entropy of every perfectly crystalline substance becomes zero. This follows from the
A. Third law of thermodynamics
B. Second law of thermodynamics
C. Nernst heat theorem
D. Maxwell's relations
Answer : A

9. For an ideal gas, the chemical potential is given by
A. RT d ln P
B. R d ln P
C. R d ln f
D. None of these
Answer : A

10. Which of the following will increase the volume of a real gas by four times?
A. Doubling the absolute temperature as well as pressure of the gas
B. Reducing pressure to one fourth at constant temperature
C. Reducing temperature to one fourth at constant pressure
D. Reducing the temperature to half and doubling the pressure
Answer : B

11. Gibbs free energy at constant pressure and temperature under equilibrium conditions is
A. ?
B. 0
C. Maximum
D. Minimum
Answer : D

12. A domestic refrigerator has a/an __________ cooled condenser.
A. Water
B. Air
C. Evaporative
D. Gas
Answer : B

13. In a homogeneous solution, the activity coefficient of a component depends upon the
A. Pressure
B. Composition
C. Temperature
D. All (A), (B) and (C)
Answer : D

14. One ton of refrigeration is defined as the heat rate corresponding to melting of one ton of ice in one
A. Hour
B. Day
C. Minute
D. Second
Answer : B

15. Joule-Thomson experiment is
A. Isobaric
B. Adiabatic
C. Isenthalpic
D. Both (B) & (C)
Answer : D

16. Pick out the wrong statement.
A. Enthalpies of all elements in their standard states are assumed to be zero
B. Combustion reactions are never endothermic in nature
C. Heat of reaction at constant volume is equal to the change in internal energy
D. Clausius-Clapeyron equation is not applicable to melting process
Answer : D

17. For a spontaneous process, free energy
A. Is zero
B. Increases
C. Decreases whereas the entropy increases
D. And entropy both decrease
Answer : C

18. The extensive properties are
A. Volume, mass and number of moles
B. Free energy, entropy and enthalpy
C. Both (A) and (B)
D. None of these
Answer : C

19. To obtain integrated form of Clausius-Clapeyron equation, ln (P₂/P₁) = (?H_V/R) (1/T₁ - 1/T₂) from the exact Clapeyron equation, it is assumed that the
A. Volume of the liquid phase is negligible compared to that of vapour phase
B. Vapour phase behaves as an ideal gas
C. Heat of vaporisation is independent of temperature
D. All (A), (B) & (C)
Answer : D

20. Fugacity co-efficient of a substance is the ratio of its fugacity to
A. Mole fraction
B. Activity
C. Pressure
D. Activity co-efficient
Answer : C

21. Work done in case of free expansion is
A. Indeterminate
B. Zero
C. Negative
D. None of these
Answer : B

22. Which of the following is not affected by temperature changes?
A. Fugacity
B. Activity co-efficient
C. Free energy
D. None of these
Answer : D

23. C_v for an ideal gas
A. Does not depend upon temperature
B. Is independent of pressure only
C. Is independent of volume only
D. Is independent of both pressure and volume
Answer : D

24. Throttling process is a/an __________ process.
A. Reversible and isothermal
B. Irreversible and constant enthalpy
C. Reversible and constant entropy
D. Reversible and constant enthalpy
Answer : B

25. For an isothermal reversible compression of an ideal gas
A. Only ?E = 0
B. Only ?H =0
C. ?E = ?H = 0
D. dQ = dE
Answer : C

26. When liquid and vapour phase of multi-component system are in equilibrium (at a given temperature and pressure), then chemical potential of each component is
A. Same in both the phases
B. Zero in both the phases
C. More in vapour phase
D. More in liquid phase
Answer : A

27. At triple point (for one component system), vapour pressure of solid as compared to that of liquid will be
A. More
B. Less
C. Same
D. More or less; depending on the system
Answer : C

28. If different processes are used to bring about the same chemical reaction, the enthalpy change is same for all of them. This is __________ law.
A. Hess's
B. Kirchoff's
C. Lavoisier and Laplace
D. None of these
Answer : A

29. Which of the following processes cannot be made reversible even under ideal condition of operation?
A. Free expansion of a gas
B. Compression of air in a compressor
C. Expansion of steam in a turbine
D. All (A), (B) & (C)
Answer : A

30. The internal energy of a gas obeying P (V - b) RT (where, b is a positive constant and has a constant C_v), depends upon its
A. Pressure
B. Volume
C. Temperature
D. All (A), (B) & (C)
Answer : C

31. With increase in pressure (above atmospheric pressure), the C_p of a gas
A. Increases
B. Decreases
C. Remains unchanged
D. First decreases and then increases
Answer : A

32. Which of the following is not an intensive property?
A. Molar heat capacity
B. Internal energy
C. Viscosity
D. None of these
Answer : B

33. When a system is in equilibrium for all possible processes, the differential or finite change of entropy is
A. < 0
B. > 0
C. = 0
D. None of these
Answer : A

34. The equation, (d log_e PA/d log_e xA) = (d log_e PA/d log_e xB) applicable to a binary solution of components. A and B in equilibrium with their vapors at constant temperature and pressure is called the __________ equation.
A. Van Laar
B. Margules
C. Gibbs-Duhem
D. Gibbs-Duhem-Margules
Answer : D

35. Adiabatic compression of a saturated water vapour makes it
A. Supersaturated
B. Superheated
C. Both (A) and (B)
D. Neither (A) nor (B)
Answer : B

36. The equation, C_p - C_v = R, is true for __________ gas.
A. No
B. Any real
C. Only ideal
D. Both (B) and (C)
Answer : C

37. Lowering of condenser temperature (keeping the evaporator temperature constant) in case of vapour compression refrigeration system results in
A. Increased COP
B. Same COP
C. Decreased COP
D. Increased or decreased COP; depending upon the type of refrigerant
Answer : A

38. The co-efficient of performance (COP) of a refrigerating system, which is its index of performance, is defined as the ratio of useful refrigeration to the net work. The units of __________ and COP are the same.
A. Kinematic viscosity
B. Work
C. Temperature
D. None of these
Answer : D

39. __________ increases with increase in pressure.
A. The melting point of wax
B. The boiling point of a liquid
C. Both (A) and (B)
D. Neither (A) nor (B)
Answer : C

40. When a gas is expanded from high pressure region to low pressure region; temperature change occurs. This phenomenon is related to the
A. Gibbs-Duhem equation
B. Gibbs-Helmholtz equation
C. Third law of thermodynamics
D. Joule-Thomson effect
Answer : D

41. The unit of fugacity is the same as that of the
A. Pressure
B. Temperature
C. Volume
D. Molar concentration
Answer : A

42. Compressibility factor of a gas is
A. Not a function of its pressure
B. Not a function of its nature
C. Not a function of its temperature
D. Unity, if it follows PV = nRT
Answer : A

43. Which is not constant for an ideal gas?
A. (?P/?V)_T
B. (?V/?T)_P
C. (?P/?V)_V
D. All (A), (B) & (C)
Answer : A

44. Pick out the wrong statement.
A. Surface tension of a substance vanishes at critical point, as there is no distinction between liquid and vapour phases at its critical point
B. Entropy of a system decreases with the evolution of heat
C. Change of internal energy is negative for exothermic reactions
D. The eccentric factor for all materials is always more than one
Answer : D

45. When a system in equilibrium is subjected to a change in temperature, pressure or concentration, the equilibrium is displaced in a direction which tends to undo the effect of the change. This is called the
A. Le-Chatelier principle
B. Kopp's rule
C. Law of corresponding state
D. Arrhenius hypothesis
Answer : A

46. Fugacity of a component in an ideal gas mixture is equal to the partial pressure of that component in the mixture. The fugacity of each component in a stable homogeneous solution at constant pressure and temperature __________ as its mole fraction increases.
A. Decreases
B. Decreases exponentially
C. Increases
D. Remain constant
Answer : C

47. Free energy change of mixing two liquid substances is a function of the
A. Concentration of the constituents only
B. Quantities of the constituents only
C. Temperature only
D. All (A), (B) and (C)
Answer : D

48. Sublimation temperature of dry ice (solid CO₂) is __________ °C.
A. -273
B. 0
C. -78
D. 5
Answer : C

49. Pick out the wrong statement.
A. The values of (?P/?V)_T and (?²P/?V²)_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 : C

50. 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
Answer : B