1000+ Chemical Engineering Thermodynamics Multiple Choice Question Answer [Solved]

1. At absolute zero temperature, the __________ of the gas is zero.
A. Pressure
B. Volume
C. Mass
D. None of these
Answer : B

2. What is the value of Joule-Thomson co-efficient for an ideal gas?
A. +ve
B. -ve
C. 0
D. ?
Answer : C

3. Boiling of liquid is accompanied with increase in the
A. Vapor pressure
B. Specific Gibbs free energy
C. Specific entropy
D. All (A), (B) and (C)
Answer : A

4. With increase in temperature, the atomic heat capacities of all solid elements
A. Increases
B. Decreases
C. Remains unchanged
D. Decreases linearly
Answer : A

5. 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

6. Which of the following represents the Virial equation of state?
A. T = [RT/(V- b)] - [a/?T. V(V + b)]
B. PV/RT = 1 + (B/V) + (C/V²) + ……
C. n₁u₂ + ?₂?₁ = 0
D. None of these
Answer : B

7. What is the ratio of adiabatic compressibility to isothermal compressibility?
A. 1
B. < 1
C. > 1
D. >> 1
Answer : B

8. In vapour compression refrigeration system, if the evaporator temperature and the condenser temperatures are -13°C and 37°C respectively, the Carnot COP will be
A. 5.2
B. 6.2
C. 0.168
D. Data insufficient, can't be found out
Answer : A

9. Which of the following is an extensive property of a system?
A. Heat capacity
B. Molal heat capacity
C. Pressure
D. Concentration
Answer : A

10. 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

11. At a given temperature, the volume of a gas dissolved in a solvent __________ with increase in pressure.
A. Increases
B. Decreases
C. Remains unchanged
D. May increase or decrease; depends on the gas
Answer : C

12. The temperature at the eutectic point of the system is the __________ temperature that can be attained in the system.
A. Lowest
B. Highest
C. Average
D. None of these
Answer : A

13. Which of the following is not correct for a reversible adiabatic process?
A. TV^?-1 = constant
B. p^1-?.T^Y = constant
C. PV^? = constant
D. None of these
Answer : D

14. The entropy change in a reversible isothermal process, when an ideal gas expands to four times its initial volume is
A. R log_e 4
B. R log₁₀ 4
C. C_v log₁₀ 4
D. C_v log_e 4
Answer : A

15. Grams of butane (C₄H₁₀) formed by the liquefaction of 448 litres of the gas (measured at (STP) would be
A. 580
B. 640
C. 1160
D. Data insufficient; can't be computed
Answer : C

16. During Joule-Thomson expansion of gases
A. Enthalpy remains constant
B. Entropy remains constant
C. Temperature remains constant
D. None of these
Answer : A

17. Which of the following is Clausius-Clapeyron Equation for vaporisation of an ideal gas under the condition that the molar volume of liquid is negligible compared to that of the vapor?
A. d ln p/dt = H_vap/RT²
B. d ln p/dt = RT²/H_vap
C. dp/dt = RT²/H_vap
D. dp/dt = H_vap/RT²
Answer : A

18. Pick out the wrong statement.
A. At constant pressure, solubility of a gas in a liquid diminishes with rise in temperature
B. Normally, the gases which are easily liquefied are more soluble in common solvents
C. The gases which are capable of forming ions in aqueous solution are much more soluble in water than in other solvents
D. At constant pressure, solubility of a gas in a liquid increases with rise in temperature
Answer : A

19. 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

20. Fugacity and pressure are numerically equal, when the gas is
A. In standard state
B. At high pressure
C. At low temperature
D. In ideal state
Answer : D

21. For the reversible exothermic reaction, N₂ + 3H₂ ? 2NH₃, increase of pressure would
A. Shift the equilibrium towards right
B. Give higher yield of NH₃
C. Both (B) and (C)
D. Neither (A) nor (B)
Answer : C

22. Pick out the wrong statement.
A. An ideal liquid or solid solution is defined as one in which each component obeys Raoult's law
B. If Raoult's law is applied to one component of a binary mixture; Henry's law or Raoult's law is applied to the other component also
C. Henry's law is rigorously correct in the limit of infinite dilution
D. None of these
Answer : D

23. The number of degree of freedom for an Azeotropic mixture of ethanol and water in vapourliquid equilibrium, is
A. 3
B. 1
C. 2
D. 0
Answer : B

24. 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

25. A gas mixture of three components is brought in contact with a dispersion of an organic phase in water. The degree of freedom of the system is
A. 3
B. 4
C. 5
D. 6
Answer : A

26. In an irreversible process
A. Tds = dE - dW = 0
B. dE - dW - Tds = 0
C. Tds - dE + dW < 0
D. Tds - dT + dW < 0
Answer : C

27. A cyclic engine exchanges heat with two reservoirs maintained at 100 and 300°C respectively. The maximum work (in J) that can be obtained from 1000 J of heat extracted from the hot reservoir is
A. 349
B. 651
C. 667
D. 1000
Answer : A

28. The standard Gibbs free energy change of a reaction depends on the equilibrium
A. Pressure
B. Temperature
C. Composition
D. All (A), (B) and (C)
Answer : B

29. Out of the following refrigeration cycles, which one has maximum COP?
A. Air cycle
B. Carnot cycle
C. Ordinary vapor compression cycle
D. Vapor compression with a reversible expansion engine
Answer : B

30. The number of degrees of freedom at the triple point of water is
A. 0
B. 1
C. 2
D. 3
Answer : A

31. The amount of heat required to decompose a compound into its elements is __________ the heat of formation of that compound from its elements.
A. Less than
B. More than
C. Same as
D. Not related to
Answer : C

32. 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

33. Pick out the wrong statement.
A. The conversion for a gas phase reaction increases with decrease in pressure, if there is an increase in volume accompanying the reaction
B. With increase in temperature, the equilibrium constant increases for an exothermic reaction
C. The equilibrium constant of a reaction depends upon temperature only
D. The conversion for a gas phase reaction increases with increase in pressure, if there is a decrease in volume accompanying the reaction
Answer : B

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

35. When a gas in a vessel expands, its internal energy decreases. The process involved is
A. Reversible
B. Irreversible
C. Isothermal
D. Adiabatic
Answer : A

36. Rotary lime kiln is an example of a/an __________ system.
A. Closed
B. Open
C. Isolated
D. Non-thermodynamic
Answer : B

37. A cylinder contains 640 gm of liquid oxygen. The volume occupied (in litres) by the oxygen, when it is released and brought to standard conditions (0°C, 760 mm Hg) will be __________ litres.
A. 448
B. 224
C. 22.4
D. Data insufficient; can't be computed
Answer : A

38. If two gases have same reduced temperature and reduced pressure, then they will have the same
A. Volume
B. Mass
C. Critical temperature
D. None of these
Answer : D

39. Clausius-Clapeyron Equation gives accurate result, when the
A. Vapour pressure is relatively low and the temperature does not vary over wide limits
B. Vapour obeys the ideal gas law and the latent heat of vaporisation is constant
C. Volume in the liquid state is negligible compared with that in the vapour state
D. All (A), (B) and (C)
Answer : D

40. 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

41. Ideal refrigeration cycle is
A. Same as Carnot cycle
B. Same as reverse Carnot cycle
C. Dependent on the refrigerant's properties
D. The least efficient of all refrigeration processes
Answer : B

42. Pick out the wrong statement pertaining to the decomposition of PCl₅ represented by, PCl₅ ? PCl₃ + Cl₂.Degree of dissociation of PCl₅ will
A. Decrease on addition of Cl₂
B. Increase on addition of an inert gas at constant pressure
C. Decrease on increasing the pressure of the system
D. None of these
Answer : D

43. Internal energy of an element at 1 atm and 25° C is __________ kcal/kg.mole.
A. 0
B. 273
C. 25
D. None of these
Answer : A

44. Melting of ice is an example of an __________ process.
A. Adiabatic
B. Isothermal
C. Isometric
D. None of these
Answer : B

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

46. Clausius-Clapeyron equation is applicable to __________ equilibrium processes.
A. Solid-vapor
B. Solid-liquid
C. Liquid-vapor
D. All (A), (B) and (C)
Answer : D

47. A refrigeration cycle is a reversed heat engine. Which of the following has the maximum value of the co-efficient of performance (COP) for a given refrigeration effect?
A. Vapor compression cycle using expansion valve
B. Air refrigeration cycle
C. Vapor compression cycle using expansion engine
D. Carnot refrigeration cycle
Answer : D

48. Entropy change of mixing two liquid substances depends upon the
A. Molar concentration
B. Quantity (i.e. number of moles)
C. Both (A) and (B)
D. Neither (A) nor (B)
Answer : C

49. Joule-Thomson co-efficient for a perfect gas is
A. Zero
B. Positive
C. Negative
D. None of these
Answer : A

50. What happens in a reversible adiabatic expansion process?
A. Heating takes place
B. Cooling takes place
C. Pressure is constant
D. Temperature is constant
Answer : B