1000+ Chemical Engineering Thermodynamics MCQ for SSC CHSL [Solved]

1. 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

2. 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

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

4. d_W and d_q are not the exact differential, because q and W are
A. State functions
B. Path functions
C. Intensive properties
D. Extensive properties
Answer : B

5. The adiabatic throttling process of a perfect gas is one of constant enthalpy
A. In which there is a temperature drop
B. Which is exemplified by a non-steady flow expansion
C. Which can be performed in a pipe with a constriction
D. In which there is an increase in temperature
Answer : C

6. Partial molar free energy of an element A in solution is same as its
A. Chemical potential
B. Activity
C. Fugacity
D. Activity co-efficient
Answer : A

7. (?E/?T)_V is the mathematical expression for
A. C_V
B. Enthalpy change
C. Free energy change
D. None of these
Answer : D

8. For an isothermal process, the internal energy of a gas
A. Increases
B. Decreases
C. Remains unchanged
D. Data insufficient, can't be predicted
Answer : C

9. The co-efficient of performance (COP) of a refrigerating system, which is its index of performance, is defined as the ratio of useful refrigeration to the net work. The units of __________ and COP are the same.
A. Kinematic viscosity
B. Work
C. Temperature
D. None of these
Answer : D

10. 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

11. As the time is passing, entropy of the universe
A. Is increasing
B. Is decreasing
C. Remain constant
D. Data insufficient, can't be predicted
Answer : A

12. 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

13. For an isothermal reversible compression of an ideal gas
A. Only ?E = 0
B. Only ?H =0
C. ?E = ?H = 0
D. dQ = dE
Answer : C

14. 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

15. When a system is in equilibrium for all possible processes, the differential or finite change of entropy is
A. < 0
B. > 0
C. = 0
D. None of these
Answer : A

16. A system is said to be at equilibrium, if the entropy of the system has reached __________ value.
A. Minimum
B. Zero
C. Maximum
D. None of these
Answer : C

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

18. 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

19. 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

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

21. 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

22. 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

23. 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

24. 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

25. Van Laar equation deals with the activity coefficients in
A. Binary solutions
B. Ternary solutions
C. Azeotropic mixture only
D. None of these
Answer : A

26. Second law of thermodynamics is concerned with the
A. Amount of energy transferred
B. Direction of energy transfer
C. Irreversible processes only
D. Non-cyclic processes only
Answer : B

27. High pressure steam is expanded adiabatically and reversibly through a well insulated turbine, which produces some shaft work. If the enthalpy change and entropy change across the turbine are represented by ?H and ?S respectively for this process:
A. ? H = 0 and ?S = 0
B. ? H ? 0 and ?S = 0
C. ? H ? 0 and ?S ? 0
D. ? H = 0 and ?S ? 0
Answer : B

28. One mole of nitrogen at 8 bar and 600 K is contained in a piston-cylinder arrangement. It is brought to 1 bar isothermally against a resisting pressure of 1 bar. The work done (in Joules) by the gas is
A. 30554
B. 10373
C. 4988.4
D. 4364.9
Answer : B

29. 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

30. In an isothermal process on an ideal gas, the pressure increases by 0.5 percent. The volume decreases by about __________ percent.
A. 0.25
B. 0.5
C. 0.75
D. 1
Answer : B

31. 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

32. If an ideal solution is formed by mixing two pure liquids in any proportion, then the __________ of mixing is zero
A. Enthalpy
B. Volume
C. Both 'a' & 'b'
D. Neither 'a' nor 'b'
Answer : C

33. Melting of ice exemplifies a/an
A. Adiabatic process
B. Endothermic reaction
C. Exothermic reaction
D. Process involving a chemical reaction
Answer : B

34. 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

35. 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

36. 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

37. The most important application of distribution law is in
A. Evaporation
B. Liquid extraction
C. Drying
D. Distillation
Answer : B

38. 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

39. Tea kept in a thermos flask is vigorously shaken. If the tea is considered as a system, then its temperature will
A. Increase
B. Decrease
C. Remain unchanged
D. First fall and then rise
Answer : A

40. Keeping the pressure constant, to double the volume of a given mass of an ideal gas at 27°C, the temperature should be raised to __________ °C.
A. 270
B. 327
C. 300
D. 540
Answer : B

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

42. The variation of heat of reaction with temperature at constant pressure is given by the __________ law.
A. Kelvin's
B. Antoines
C. Kirchoffs
D. None of these
Answer : C

43. Heat requirement for decomposition of a compound into its elements is __________ that is evolved during the formation of that compound from its elements.
A. The same
B. Less than
C. Greater than
D. Different than
Answer : A

44. In polytropic process (PVⁿ = constant), if n = 1; it means a/an __________ process.
A. Adiabatic
B. Reversible
C. Isothermal
D. None of these
Answer : C

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

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

47. (1/V) (?V/?T)_P is the mathematical expression
A. Joule-Thomson co-efficient
B. Specific heat at constant pressure (C_p)
C. co-efficient of thermal expansion
D. Specific heat at constant volume (C_V)
Answer : C

48. Free energy change at equilibrium is
A. Zero
B. Positive
C. Negative
D. Indeterminate
Answer : A

49. The heat capacities for the ideal gas state depend upon the
A. Pressure
B. Temperature
C. Both (A) & (B)
D. Neither (A) nor (B)
Answer : B

50. In case of an __________ process, the temperature of the system increases.
A. Isothermal compression
B. Isothermal expansion
C. Adiabatic expansion
D. Adiabatic compression
Answer : D