1000+ Chemical Engineering Thermodynamics MCQ for RBI Assistant [Solved]

1. Which of the following is a widely used refrigerant in vapour compression refrigeration system (using large centrifugal compressor)?
A. Freon
B. Liquid sulphur dioxide
C. Methyl chloride
D. Ammonia
Answer : A

2. Entropy of an ideal gas depends upon its
A. Pressure
B. Temperature
C. Both (A) & (B)
D. Neither (A) nor (B)
Answer : C

3. 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

4. The compressibility factor for an ideal gas is 1. Its value for any other real gas is
A. 1
B. < 1
C. > 1
D. Either (B) or (C), depends on the nature of the gas
Answer : D

5. Equilibrium constant decreases as the temperature
A. Increases, for an exothermic reaction
B. Decreases, for an exothermic reaction
C. Increases, for an endothermic reaction
D. None of these
Answer : A

6. __________ does not change during phase transformation processes like sublimation, melting & vaporisation.
A. Entropy
B. Gibbs free energy
C. Internal energy
D. All (A), (B) & (C)
Answer : B

7. In any spontaneous process,
A. Only F decreases
B. Only A decreases
C. Both F and A decreases
D. Both F and A increase
Answer : C

8. 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
Answer : D

9. Measurement of thermodynamic property of temperature is facilitated by __________ law of thermodynamics.
A. 1st
B. Zeroth
C. 3rd
D. None of these
Answer : B

10. 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

11. Henry's law is closely obeyed by a gas, when its __________ is extremely high.
A. Pressure
B. Solubility
C. Temperature
D. None of these
Answer : D

12. All gases except __________ shows a cooling effect during throttling process at atmospheric temperature and pressure.
A. Oxygen
B. Nitrogen
C. Air
D. Hydrogen
Answer : D

13. Pick out the correct equation relating 'F' and 'A'.
A. F = A + PV
B. F = E + A
C. F = A - TS
D. F = A + TS
Answer : A

14. Melting of wax is accompanied with __________ in entropy.
A. Increase
B. Decrease
C. No change
D. None of these
Answer : A

15. 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

16. The four properties of a system viz. P, V, T, S are related by __________ equation.
A. Gibbs-Duhem
B. Gibbs-Helmholtz
C. Maxwell's
D. None of these
Answer : C

17. Pick out the correct statement.
A. A real gas on expansion in vacuum gets heated up
B. An ideal gas on expansion in vacuum gets cooled
C. An ideal gas on expansion in vacuum gets heated up
D. A real gas on expansion in vacuum cools down whereas ideal gas remains unaffected
Answer : D

18. 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

19. The value of Joule-Thomson co-efficient, in case where cooling occurs after the throttling process is
A. 0
B. ?
C. +ve
D. -ve
Answer : C

20. In the reaction; N₂ + O₂ ? 2NO, increasing the pressure will result in
A. Shifting the equilibrium towards right
B. Shifting the equilibrium towards left
C. No change in equilibrium condition
D. None of these
Answer : C

21. If the internal energy of an ideal gas decreases by the same amount as the work done by the system, then the
A. Process must be isobaric
B. Temperature must decrease
C. Process must be adiabatic
D. Both (B) and (C)
Answer : D

22. Which of the following is a thermodynamic property of a system?
A. Concentration
B. Mass
C. Temperature
D. Entropy
Answer : D

23. Which of the following is not a common refrigerant?
A. Freon-12
B. Ethylene
C. Ammonia
D. Carbon dioxide
Answer : B

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

25. 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

26. During a reversible isothermal expansion of an ideal gas, the entropy change is
A. +ve
B. 0
C. -ve
D. ?
Answer : A

27. Standard temperature and pressure (S.T.P.) is
A. 0°C and 750 mm Hg
B. 15°C and 750 mm Hg
C. 0°C and 1 kgf/cm2
D. 15°C and 1 kgf/cm2
Answer : A

28. A gas has a volume of 27.3 c.c. at 0°C. Its volume at 10°C (if pressure remains unchanged) will be __________ c.c.
A. 2.73
B. 28.3
C. 273
D. 283
Answer : B

29. For an exothermic reaction
A. Only enthalpy change (?H) is negative
B. Only internal energy change (?E) is negative
C. Both ?H and ?E are negative
D. Enthalpy change is zero
Answer : C

30. In the equation, PVⁿ = constant, if the value of n is in between 1 and y (i.e. C_p/C_v), then it represents a reversible __________ process.
A. Isometric
B. Polytropic
C. Isentropic
D. Isobaric
Answer : B

31. In an ideal solution, the activity of a component equals its
A. Mole fraction
B. Fugacity at the same temperature and pressure
C. Partial pressure
D. None of these
Answer : A

32. What is the value of maximum COP in case of absorption refrigeration, if refrigeration provided is at temperature, T_R (where, T₁ and T₂ are source & surrounding temperatures respectively.)?
A. T_R/(T₂ - T_R) × (T₁ - T₂)/T₁
B. T_R/(T₂ - T_R) × T₁/(T₁ - T₂)
C. T_R/(T₁ - T_R) × (T₁ - T₂)/T₁
D. None of these
Answer : A

33. __________ functions are exemplified by heat and work.
A. Path
B. Point
C. State
D. None of these
Answer : A

34. Minimum number of phases that exists in a system is 1. Number of chemical species in a colloidal system is
A. 1
B. 2
C. 3
D. 4
Answer : B

35. First law of thermodynamics is mathematically stated as
A. dQ = dE + dW
B. dQ = dE - dW
C. dE = dQ + dW
D. dW = dQ + dE
Answer : A

36. In case of a close thermodynamic system, there is __________ across the boundaries.
A. No heat and mass transfer
B. No mass transfer but heat transfer
C. Mass and energy transfer
D. None of these
Answer : B

37. 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

38. Pick out the undesirable property for a good refrigerant.
A. High thermal conductivity
B. Low freezing point
C. Large latent heat of vaporisation
D. High viscosity
Answer : D

39. In an ideal gas mixture, fugacity of a species is equal to its
A. Vapor pressure
B. Partial pressure
C. Chemical potential
D. None of these
Answer : B

40. Joule-Thomson co-efficient depends on the
A. Pressure
B. Temperature
C. Both (A) & (B)
D. Neither (A) nor (B)
Answer : C

41. For the gaseous phase chemical reaction, C₂H₄(g) + H₂O(g) ? C₂H₅OH(g), the equilibrium conversion does not depend on the
A. Steam to ethylene ratio
B. Temperature
C. Pressure
D. None of these
Answer : D

42. The relation connecting the fugacities of various components in a solution with one another and to composition at constant temperature and pressure is called the __________ equation.
A. Gibbs-Duhem
B. Van Laar
C. Gibbs-Helmholtz
D. Margules
Answer : A

43. Compressibility factor (i.e., the ratio of actual volume of gas to the volume predicted by ideal gas law) for all gases are
A. Always greater than one
B. Same at the same reduced temperature
C. Same at the same reduced pressure
D. Both (B) & (C)
Answer : D

44. Which of the following non-flow reversible compression processes require maximum work?
A. Adiabatic process
B. Isothermal process
C. Isobaric process
D. All require same work
Answer : A

45. The number of degrees of freedom for a mixture of ice and water (liquid) are
A. 3
B. 2
C. 1
D. 0
Answer : C

46. Isentropic process means a constant __________ process.
A. Enthalpy
B. Pressure
C. Entropy
D. None of these
Answer : C

47. Equation which relates pressure, volume and temperature of a gas is called the
A. Equation of state
B. Gibbs Duhem equation
C. Ideal gas equation
D. None of these
Answer : A

48. Pick out the extensive property out of the following.
A. Surface tension
B. Free energy
C. Specific heat
D. Refractive index
Answer : B

49. If the pressure on 100 c.c. of air is halved, then its volume (at the same temperature) would be __________ c.c.
A. 100
B. 50
C. 205
D. 200
Answer : D

50. If we increase the pressure on a substance (which is at its triple point), then the triple point
A. Increases
B. Decreases
C. Remains unchanged
D. May increase or decrease; depends on the substance
Answer : C