1000+ Chemical Engineering Thermodynamics MCQ for RRB JE [Solved]

1. Which is an example of closed system?
A. Air compressor
B. Liquid cooling system of an automobile
C. Boiler
D. None of these
Answer : B

2. Heat of reaction at constant volume is identified with __________ change.
A. Enthalpy
B. Internal energy
C. Either (A) or (B)
D. Neither (A) nor (B)
Answer : B

3. Law of corresponding states says that
A. Two different gases behave similarly, if their reduced properties (i.e. P, V and T) are same
B. The surface of separation (i. e. the meniscus) between liquid and vapour phase disappears at the critical temperature
C. No gas can be liquefied above the critical temperature, howsoever high the pressure may be.
D. The molar heat of energy of gas at constant volume should be nearly constant (about 3 calories)
Answer : A

4. Change of heat content when one mole of compound is burnt in oxygen at constant pressure is called the
A. Calorific value
B. Heat of reaction
C. Heat of combustion
D. Heat of formation
Answer : C

5. At the critical point of a substance
A. The surface tension vanishes
B. Liquid and vapour have the same density
C. There is no distinction between liquid and vapour phases
D. All (A), (B) and (C)
Answer : D

6. 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

7. 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

8. 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

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

10. The rate at which a substance reacts is proportional to its active mass and the rate of a chemical reaction is proportional to the product of active masses of the reacting substances. This is the
A. Lewis-Randall rule
B. Statement of Van't Hoff Equation
C. Le-Chatelier's principle
D. None of these
Answer : D

11. In the reaction, C + O₂ ? CO₂; ?H = - 94 kcal. What is the heat content (enthalpy) of O₂?
A. -94 kcal
B. > -94 kcal
C. < - 94 kcal
D. Zero
Answer : D

12. 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

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

14. Change of state namely evaporation condensation, freezing and melting is an __________ process.
A. Isothermal
B. Adiabatic
C. Isobaric
D. Isochoric
Answer : A

15. Molar heat capacity of water in equilibrium with ice at constant pressure is __________ Kcal/kg mole. °K
A. 0
B. ?
C. 50
D. 100
Answer : B

16. The total change in the enthalpy of a system is independent of the
A. Number of intermediate chemical reactions involved
B. Pressure and temperature
C. State of combination and aggregation in the beginning and at the end of the reaction
D. None of these
Answer : A

17. Filling of gas from a high pressure cylinder into small bottles is an example of a/an __________ process.
A. Equilibrium
B. Adiabatic
C. Steady
D. Unsteady
Answer : D

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

19. The ratio of equilibrium constants (Kp2/Kp1) at two different temperatures is given by
A. (R/?H) (1/T₁ - 1/T₂)
B. (?H/R) (1/T₁ - 1/T₂)
C. (?H/R) (1/T₂ - 1/T₁)
D. (1/R) (1/T₁ - 1/T₂)
Answer : B

20. For an irreversible process involving only pressure-volume work
A. (dF)_T, p <0
B. (dF)_T, p = 0
C. (dF)_T, p > 0
D. (dA)_T, v >0
Answer : A

21. Which of the following is Virial equation of state?
A. (p + a/V²)(V - b) = nRT
B. PV = nRT
C. PV = A + B/V + C/V² + D/V³ + ...
D. None of these
Answer : C

22. The expression for entropy change given by, ?S = - nR ln (P₂/P₁), holds good for
A. Expansion of a real gas
B. Reversible isothermal volume change
C. Heating of an ideal gas
D. Cooling of a real gas
Answer : B

23. Boyle's law for gases states that
A. P ? 1/V, when temperature is constant
B. P ? 1/V, when temperature & mass of the gas remain constant
C. P ? V, at constant temperature & mass of the gas
D. P/V = constant, for any gas
Answer : B

24. Which of the following is an undesirable characteristic of a refrigerant?
A. It should be non-explosive
B. It should have a sub-atmospheric vapor pressure at the temperature in refrigerator coils
C. Its vapor pressure at the condenser temperature should be very high
D. None of these
Answer : B

25. The expression for entropy change, ?S = n C_p . ln (T₂/T₁), is valid for the __________ of a substance.
A. Simultaneous pressure & temperature change
B. Heating
C. Cooling
D. Both (B) and (C)
Answer : D

26. 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

27. In a reversible chemical reaction (where, ?x = number of moles of products-number of moles of reactants)
A. Addition of inert gas favours the forward reaction, when ?x is positive
B. Pressure has no effect on equilibrium, when ?n = 0
C. Addition of inert gas has no effect on the equilibrium constant at constant volume for any value of ?x (+ ve, - ve) or zero)
D. All 'a', 'b' & 'c'
Answer : D

28. Refrigeration capacity of a household refrigerator may be round about __________ tons.
A. 0.15
B. 1.5
C. 4.5
D. 6.5
Answer : A

29. __________ 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

30. Reduced pressure of a gas is the ratio of its
A. Pressure to critical pressure
B. Critical pressure to pressure
C. Pressure to pseudocritical pressure
D. Pseudocritical pressure to pressure
Answer : A

31. 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

32. Co-efficient of Performance (COP) of a refrigerator is the ratio of the
A. Work required to refrigeration obtained
B. Refrigeration obtained to the work required
C. Lower to higher temperature
D. Higher to lower temperature
Answer : B

33. For water at 300°C, it has a vapour pressure 8592.7 kPa and fugacity 6738.9 kPa Under these conditions, one mole of water in liquid phase has a volume of 25.28 cm3 and that in vapour phase in 391.1 cm3.Fugacity of water (in kPa) at 9000 kPa will be
A. 6738.9
B. 6753.5
C. 7058.3
D. 9000
Answer : B

34. As the temperature is lowered towards the absolute zero, the value of ?(?F)/?T, then approaches
A. Unity
B. Zero
C. That of the heat of reaction
D. Infinity
Answer : B

35. Heat pump
A. Accomplishes only space heating in winter
B. Accomplishes only space cooling in summer
C. Accomplishes both (A) and (B)
D. Works on Carnot cycle
Answer : C

36. 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

37. In a working refrigerator, the value of COP is always
A. 0
B. < 0
C. < 1
D. > 1
Answer : D

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

39. 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

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

41. The quantitative effect of temperature on chemical equilibrium is given by the
A. Vant-Hoff equation
B. Le-Chatelier's principle
C. Arrhenius equation
D. None of these
Answer : A

42. Equilibrium constant of a reaction varies with the
A. Initial oncentration of the reactant
B. Pressure
C. Temperature
D. None of these
Answer : C

43. The minimum number of phases that can exist in a system is
A. 0
B. 1
C. 2
D. 3
Answer : B

44. A gas shows deviation from ideal behaviour at
A. Low pressure and high temperature
B. Low pressure and low temperature
C. Low temperature and high pressure
D. High temperature and high pressure
Answer : C

45. 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

46. 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

47. 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

48. In case of vapour compression refrigeration system, elevating the evaporator temperature (keeping the condenser temperature constant) results in
A. Enhanced COP
B. Decreased COP
C. No change in the value of COP
D. Increased or decreased COP; depending upon the type of refrigerant
Answer : A

49. 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

50. After throttling, gas temperature
A. Decreases
B. Increases
C. Remain same
D. May increase or decrease; depends on the nature of the gas
Answer : A