RRB Group D - Chemical Engineering Thermodynamics 1000+ MCQ [Solved] PDF Download

1. Ideal gas law is applicable at
A. Low T, low P
B. High T, high P
C. Low T, high P
D. High T, low P
Answer : D

2. 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

3. 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

4. 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

5. Pick out the correct statement:
A. In an isothermal system, irreversible work is more than reversible work
B. Under reversible conditions, the adiabatic work is less than isothermal work
C. Heat, work, enthalpy and entropy are all 'state functions'
D. Matter and energy cannot be exchanged with the surroundings in a closed system
Answer : B

6. An isolated system can exchange __________ with its surroundings.
A. Matter
B. Energy
C. Neither matter nor energy
D. Both matter and energy
Answer : C

7. 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

8. Which of the following is not an intensive property?
A. Volume
B. Density
C. Temperature
D. Pressure
Answer : A

9. Work done in an adiabatic process between two states depends on the
A. Rate of heat transmission
B. Initial state only
C. End states only
D. None of these
Answer : C

10. A Carnot cycle consists of the following steps:
A. Two isothermal and two isentropic
B. Two isobaric and two isothermal
C. Two isochoric and two isobaric
D. Two isothermals and two isochoric
Answer : A

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

12. 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

13. Fugacity is most helpful in
A. Representing actual behaviour of real gases
B. Representing actual behaviour of ideal gases
C. The study of chemical equilibria involving gases at atmospheric pressure
D. None of these
Answer : A

14. Which of the following is not a unit of the equilibrium constant K_p? (where, ?x = number of moles of products number of moles of reactants)
A. (atm)^?x, when ?x is negative
B. (atm)^?x, when ?x is positive
C. Dimensionless, when ?x = 0
D. (atm)^?x2, when ?x > 0
Answer : D

15. 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

16. Linde gas liquefaction process employs cooling
A. By throttling
B. By expansion in an engine
C. At constant pressure
D. None of these
Answer : A

17. The free energy change for a chemical reaction is given by (where, K = equilibrium constant)
A. RT ln K
B. -RT ln K
C. -R ln K
D. T ln K
Answer : B

18. In a reversible process
A. Tds = dE + dW
B. dE - dW = Tds
C. dW - dE = Tds
D. Tds - dW + dE >0
Answer : A

19. 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

20. Pick out the correct statement.
A. Compression ratio of an Otto engine is comparatively higher than a diesel engine
B. Efficiency of an Otto engine is higher than that of a diesel engine for the same compression ratio
C. Otto engine efficiency decreases with the rise in compression ratio, due to decrease in work produced per quantity of heat
D. Diesel engine normally operates at lower compression ratio than an Otto engine for an equal output of work
Answer : B

21. 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

22. 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

23. For an incompressible fluid, the __________ is a function of both pressure as well as temperature.
A. Internal energy
B. Enthalpy
C. Entropy
D. All (A), (B) & (C)
Answer : B

24. __________ Equation predicts the activity coefficient from experimental data.
A. Lewis-Randall
B. Margules
C. Van Laar
D. Both (B) & (C)
Answer : D

25. Enthalpy of a gas depends upon its
A. Temperature
B. Mass
C. Volume
D. Pressure
Answer : A

26. Which of the following is not a reversible process?
A. Expansion of an ideal gas against constant pressure
B. Atmospheric pressure vaporisation of water at 100°C
C. Solution of NaCl in water at 50°C
D. None of these
Answer : C

27. For a thermodynamic system containing 'x' chemical species, the maximum number of phases that can co-exist at equilibrium is
A. x
B. x + 1
C. x + 2
D. x + 3
Answer : C

28. At 60° C, vapour pressure of methanol and water are 84.562 kPa and 19.953 kPa respectively. An aqueous solution of methanol at 60° C exerts a pressure of 39.223 kPa; the liquid phase and vapour phase mole fractions of methanol are 0.1686 and 0.5714 respectively. Activity co-efficient of methanol is
A. 1.572
B. 1.9398
C. 3.389
D. 4.238
Answer : A

29. Critical compressibility factor for all substances
A. Are more or less constant (vary from 0.2 to 0.3)
B. Vary as square of the absolute temperature
C. Vary as square of the absolute pressure
D. None of these
Answer : A

30. Entropy is a/an
A. State function
B. Macroscopic property
C. Extensive property
D. None of these
Answer : D

31. 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

32. Domestic refrigerator usually works on the __________ refrigeration cycle.
A. Carnot
B. Air
C. Absorption
D. vapour-ejection
Answer : C

33. On opening the door of an operating refrigerator kept in a closed room, the temperature of the room will
A. Increase
B. Decrease
C. Remain same
D. Increase in summer and will decrease in winter
Answer : A

34. For multi-component multiple phases to be in equilibrium at the same pressure and temperature, the __________ of each component must be same in all phases.
A. Chemical potential
B. Fugacity
C. Both (A) and (B)
D. Neither (A) nor (B)
Answer : C

35. Critical temperature is defined as the temperature above which a gas will
A. Not liquify (barring exceptions)
B. Immediately liquify
C. Never liquify however high the pressure may be
D. None of these
Answer : C

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

37. When dilute aqueous solutions of two salts are mixed, the process is associated with
A. Decrease in temperature
B. Increase in temperature
C. No change in temperature
D. Change in temperature which is a function of composition
Answer : B

38. 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

39. There is a change in __________ during the phase transition.
A. Volume
B. Pressure
C. Temperature
D. All a, b & c
Answer : A

40. Degree of freedom of the system ice-watervapour will be
A. 0
B. 1
C. 2
D. 3
Answer : A

41. Translational kinetic energy of molecules of an ideal gas is proportional to (where, T = absolute temperature of the gas)
A. T
B. ?T
C. T²
D. 1/?T
Answer : A

42. Fugacity is a measure of the
A. Escaping tendencies of the same substance in different phases of a system
B. Relative volatility of a mixture of two miscible liquids
C. Behaviour of ideal gases
D. None of these
Answer : A

43. The expression for entropy change given by, ?S = nR ln (V₂/V₁) + nC_v ln (T₂/T₁) is valid for
A. Reversible isothermal volume change
B. Heating of a substance
C. Cooling of a substance
D. Simultaneous heating and expansion of an ideal gas
Answer : D

44. Third law of thermodynamics is helpful in
A. Prediction of the extent of a chemical reaction
B. Calculating absolute entropies of substances at different temperature
C. Evaluating entropy changes of chemical reaction
D. Both (B) and (C)
Answer : D

45. Specific volume of an ideal gas is
A. Equal to its density
B. The reciprocal of its density
C. Proportional to pressure
D. None of these
Answer : B

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

47. 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

48. Activity co-efficient is a measure of the
A. Departure from ideal solution behaviour
B. Departure of gas phase from ideal gas law
C. Vapour pressure of liquid
D. None of these
Answer : A

49. For a given substance at a specified temperature, activity is __________ to fugacity.
A. Directly proportional
B. Inversely proportional
C. Equal
D. None of these
Answer : A

50. 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