1000+ Chemical Engineering Thermodynamics MCQ for GMAT [Solved]

1. The main feature of Carnot refrigeration cycle is that, it
A. Does not need the addition of external work for its functioning
B. Transfers heat from high temperature to low temperature
C. Accomplishes the reverse effect of the heat engine
D. None of these
Answer : C

2. The chemical potential of any constituent of an ideal solution depends on the __________ of the solution.
A. Temperature
B. Pressure
C. Composition
D. All (A), (B) and (C)
Answer : D

3. For an ideal gas, the activity co-efficient is
A. Directly proportional to pressure
B. Inversely proportional to pressure
C. Unity at all pressures
D. None of these
Answer : C

4. For an ideal gas, the internal energy depends upon its __________ only.
A. Molecular size
B. Temperature
C. Volume
D. Pressure
Answer : B

5. Which is not a refrigerant?
A. SO₂
B. NH₃
C. CCl₂F₂
D. C₂H₄Cl₂
Answer : D

6. 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

7. The enthalpy change when ammonia gas is dissolved in water is called the heat of
A. Solution
B. Formation
C. Dilution
D. Combustion
Answer : A

8. A change in state involving a decrease in entropy can be spontaneous, only if
A. It is exothermic
B. It is isenthalpic
C. It takes place isothermally
D. It takes place at constant volume
Answer : A

9. While dissolving a gas into a liquid at a constant temperature, the ratio of the concentration of the gas in the solution phase and in the gaseous phase is
A. Infinity
B. Unity
C. Constant
D. Negative
Answer : C

10. The expression, nC_v(T₂ - T₁), is for the __________ of an ideal gas.
A. Work done under adiabatic condition
B. Co-efficient of thermal expansion
C. Compressibility
D. None of these
Answer : A

11. For a stable phase at constant pressure and temperature, the fugacity of each component in a binary system __________ as its mole fraction increases.
A. Decreases
B. Increases
C. Remain same
D. Decreases linearly
Answer : B

12. An isentropic process is carried out at constant
A. Volume
B. Pressure
C. Temperature
D. All (A), (B) and (C)
Answer : A

13. Which of the following decreases with increase in pressure?
A. Melting point of ice
B. Melting point of wax
C. Boiling point of liquids
D. None of these
Answer : A

14. 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

15. For a single component two phase mixture, the number of independent variable properties are
A. Two
B. One
C. Zero
D. Three
Answer : B

16. As the temperature is lowered towards the absolute zero, the value of the quantity (??F/?T) approaches
A. Zero
B. Unity
C. Infinity
D. None of these
Answer : A

17. For an ideal gas, the enthalpy
A. Increases with rise in pressure
B. Decreases with rise in pressure
C. Is independent of pressure
D. Is a path function
Answer : C

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

19. For spontaneous changes in an isolated system (S = entropy)
A. ds = 0
B. ds <0
C. ds > 0
D. ds = Constant
Answer : C

20. The difference between isothermal compressibility and adiabatic compressibility for an ideal gas is
A. 0
B. +ve
C. -ve
D. ?
Answer : B

21. The equation relating E, P, V and T which is true for all substances under all conditions is given by (?E/?V)_T = T(?P/?T)_H - P. This equation is called the
A. Maxwell's equation
B. Thermodynamic equation of state
C. Equation of state
D. Redlich-Kwong equation of state
Answer : B

22. 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

23. In jet refrigerators, the refrigerating fluid is practically always
A. Water
B. Ammonia
C. Freon
D. Brine
Answer : A

24. The internal energy of an ideal gas does not change in a reversible __________ process.
A. Isothermal
B. Adiabatic
C. Isobaric
D. Isometric
Answer : A

25. Internal energy is equal to the heat absorbed in case of a/an __________ process.
A. Constant volume
B. Polytropic
C. Adiabatic
D. Constant pressure
Answer : A

26. The internal energy of an ideal gas is a function of its __________ only.
A. Molecular size
B. Volume
C. Pressure
D. Temperature
Answer : D

27. A gas performs the maximum work, when it expands
A. Non-uniformly
B. Adiabatically
C. Isobarically
D. Isothermally
Answer : C

28. 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

29. Dry ice is
A. Moisture free ice
B. Solid helium
C. Solid carbon dioxide
D. None of these
Answer : C

30. Pick out the correct statement.
A. Entropy and enthalpy are path functions
B. In a closed system, the energy can be exchanged with the surrounding, while matter cannot be exchanged
C. All the natural processes are reversible in nature
D. Work is a state function
Answer : C

31. Which of the following exemplifies an adiabatic process?
A. Melting of ice
B. Condensation of alcohol vapor
C. Sudden bursting of a cycle tube
D. Evaporation of water
Answer : C

32. The root mean square speed of molecules of a gas is equal to (where, m = mass of the molecule K = Boltzmanns constant, T = absolute temperature)
A. ?(2KT/m)
B. ?(3KT/m)
C. ?(6KT/m)
D. 3KT/m
Answer : B

33. The second law of thermodynamics states that
A. The energy change of a system undergoing any reversible process is zero
B. It is not possible to transfer heat from a lower temperature to a higher temperature
C. The total energy of system and surrounding remains the same
D. None of the above
Answer : D

34. Entropy, which is a measure of the disorder of a system, is:
A. Independent of pressure
B. Independent of temperature
C. Zero at absolute zero temperature for a perfect crystalline substance
D. All (A), (B) & (C)
Answer : C

35. 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

36. The gas law (PV = RT) is true for an __________ change.
A. Isothermal
B. Adiabatic
C. Both (A) & (B)
D. Neither (A) nor (B)
Answer : C

37. Chemical engineering thermodynamics is concerned with the __________ in/of chemical processes.
A. Reaction mechanism
B. Calculation of rates
C. Energy transformation from one form to another
D. None of these
Answer : C

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

39. The efficiency of an Otto engine compared to that of a diesel engine, for the same compression ratio will be
A. More
B. Less
C. Same
D. Data insufficient to predict
Answer : A

40. A solid metallic block weighing 5 kg has an initial temperature of 500°C. 40 kg of water initially at 25°C is contained in a perfectly insulated tank. The metallic block is brought into contact with water. Both of them come to equilibrium. Specific heat of block material is 0.4 kJ.kg^-1. K^-1. Ignoring the effect of expansion and contraction and also the heat capacity to tank, the total entropy change in kJ.kg^-1, K^-1 is
A. -1.87
B. 0
C. 1.26
D. 3.91
Answer : B

41. A solute distributes itself between two nonmiscible solvents in contact with each other in such a way that, at a constant temperature, the ratio of its concentrations in two layers is constant, irrespective of its total amount. This is
A. The distribution law
B. Followed from Margules equation
C. A corollary of Henry's law
D. None of these
Answer : A

42. Air-refrigeration cycle
A. Is the most efficient of all refrigeration cycles
B. Has very low efficiency
C. Requires relatively large quantities of air to achieve a significant amount of refrigeration
D. Both (B) and (C)
Answer : D

43. 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)
Answer : D

45. Third law of thermodynamics is concerned with the
A. Value of absolute entropy
B. Energy transfer
C. Direction of energy transfer
D. None of these
Answer : A

46. 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

47. The following heat engine produces power of 100,000 kW. The heat engine operates between 800 K and 300 K. It has a thermal efficiency equal to 50% of that of the Carnot engine for the same temperature. The rate at which heat is absorbed from the hot reservoir is
A. 100,000 kW
B. 160,000 kW
C. 200,000 kW
D. 320,000 kW
Answer : D

48. Gibbs free energy per mole for a pure substance is equal to the
A. Latent heat of vaporisation
B. Chemical potential
C. Molal boiling point
D. Heat capacity
Answer : B

49. Generation of heat by friction is an example of a/an __________ change.
A. Isothermal
B. Irreversible
C. Adiabatic
D. Reversible
Answer : B

50. (?T/?P)H is the mathematical expression for
A. Specific heat at constant pressure (C_p)
B. Specific heat at constant volume (C_v)
C. Joule-Thompson co-efficient
D. None of these
Answer : C