Thermodynamics

Thermodynamics

1. Which of the following equation is TRUE for an ideal gas? 
(a) temperature only
(b) temperature and pressure
(c) temperature, pressure and Gibbs free energy 

2. Mark the following variables as either Intensive property (A) or Extensive property (B) 
(i) Composition (ii) Pressure (iii) Temperature (iv) Total volume (v) Specific volume (vi) Total enthalpy (vii) molar entropy 

3. Mark the following systems as Open system (A) or Closed system (B) or Isolated system (C) 
(i) Water contained in a Dewar flask
(ii) Water contained in a sealed container is being heated
(iii) Water contained in a beaker open to atmosphere is being heated 

4. Match the following temperature scales as
(A) or 0F (B) or K (C) or 0C (D)  0

5. Match the following values of R (Universal gas constant) 
(A) 10.73 (B) 1.987 (C) 0.7302 (D) 0.0821 

6. Match the following as 
Boyles’ law (A) Charle’s law (Isobaric) (B) Charles law (Isometric) (C) General law (D)
(i) Pv/T = constant (ii) vT = constant (iii) PT = constant (iv) Pv = constant 

7. Match the following : 
Avagadro’s hypothesis (AGay Lussac’s law (B) Gibbs-Dalton’s law (C) Graham’s law (D) 
(i) Total pressure of a mixture of gases that do not react with each other is equal to the partial pressures of each of the constituent gases 
(ii) At a fixed temperature and pressure reacting gases combine with each other inn simple whole number of proportions of volume 
(iii) Equal volume of gases at the same temperature and pressure contain the same number of gas molecules 
(iv) At the same temperature and pressure the rates of diffusion of gases are inversely proportional to the square roots of their densities 

8. STP (the Standard Temperature and Pressure) is 
(a) 0°C and 1 atm. (b) 25°C and 1 atm. (c) 0 K and 1 atm.

9. For solids and liquid (far away from critical point) which of the following approximation are true. 
(a) h page2image58359808u (b) Cpage2image58360016C(c) (d) all of the above 

10. For an ideal gas enthalpy 
(a) Increases with pressure (b) Decreases with pressure. (c) Independent of changes in pressure 

11. Natural gas containing CH(77%), CO(4%), C2H(5%) and rest Nis compressed to a pressure of 2 atm. What is the partial pressure (atm) of CH4
(a) 1.54 (b) 0.46 (c) 2.39 

12. Natural gas is stored in a LPG bullet of 20mat a temperature of 400 K and 1.013 x 10kPa. What is the molar density of natural gas (assume ideal gas) ? 
(a) 30.46 mol/m(b) 1.523 mol/m(c) 3.046 mol/m

13. Instead of natural gas, air (also assume ideal) is stored at same bullet under identical conditions. What would be the molar density of air? Average mol wt of natural gas = 19.50 kg/kmol and that of air = 28.8 kg/kmol. 
(a) 30.46 m(b) 1.523 (c) 44.9 (d) 20.6 

14. An adiabatic steady state turbine is the source for a small electric generator. Steam the motive fluid, enters at 600°C and 10 bar. Steam is exhausted from the turbine 1 atm pressure and 400°C. Estimate the work done by turbine (kJ/kg steam) . 
(a) –401.7 (b) 401.7 (c) –632.2 (d) 632.2 

15. What is the amount of work done by a compressor (kJ/kmol) to compress an ideal gas isothermally at a temperature of 25°C from 1 bar to 10 bars? 
(a) 5707.7 (b) 3293 (c) 57.07 

16. An ideal gas at 35 bar and 600K leaks through a valve to an exit pressure of 7 bar. What would be the exit temperature? 
(a) 523.5K (b) 600K (c) 783.7K (d) None of these. 

17. Nitrogen gas is stored in a 2 ftcylinder at a pressure of 3000 psia and temperature of 650F. What is the molar density assuming nitrogen to be an ideal gas? 
(a) 0.532 (b) 0.192 (c) 1.798 

18. A cylinder (L1) containing LPG at 10 bars and 298 K is connected and is being used to fill another cylinder(L) initially at 1 bar and 298 K. The final temperature of Lis Tand that of Lis T2. Then 
(a) T> T(b) T= T(c) T< T

19. What would be the entropy change (J/mol.K) due to the above filling process? 
(a) 0 (b) 2.364 (c) 5.763 (d) None of these. 

20 i) dU=CVdT is true for ... 
(a) For a reversible process only.
(b) For an irreversible process only.
(c) For both reversible and irreversible processes. 

20 ii). In a well-isolated bomb calorimeter nitrogen and hydrogen react to form ammonia. . Which of the following is true? 
(a) Total enthalpy remains constant.
(b) Total internal energy remains constant. 
(c) Total entropy remains constant.

21. For an ideal gas specific internal energy is a function of 
(a) temperature only
(b) temperature and pressure
(c) temperature, pressure and Gibbs free energy 

22. The constant pressure heat capacity is given by ?
23. The constant volume heat capacity is given by ?
24. For an ideal gas the Cand Care functions of 
(a) temperature only (b) pressure only (c) both temperature and pressure 

25. The values of Cand Cfor a monatomic gas are 
(a) 5 and 3. (b) 3.987 and 1.987. (c) 0.66 and 1.987. (d) None of the above. 

26. A well designed and insulated turbine can be assumed to operate at 
(a) constant specific internal energy of the motive fluid
(b) constant specific enthalpy of the motive fluid
(c) constant specific entropy of the motive fluid
(d) constant temperature of the motive fluid 

27. Two perfectly insulate tanks of equal volume are connected to each other. Initially tank 1 (L1) contains LPG at 2 bar and 290 K and tank 2 (L2) is completely evacuated. The valve between the tanks is opened and the pressures of the two tanks are allowed to equalize. Assuming LPG to be an ideal gas what is the final temperature in tank L
(a) > 290 K     (b) 290 K        (c) > 290 K 

28. A system consists of mixture of ice and water, amount of ice being 0.5 mol and water being 0.5 mol. What is the sp. heat of the mixture ? (sp heat of water is 18 cal/mol.K and that of ice is 9 cal/mol.K ) 
(a) CP,mixture = 0         (b) CP,mixture = 18       (c) CP,mixture = 9         (d) CP,mixture = ∞ 

29. Which of the following plots is called Mollier diagram? 
(a) h-s              (b) h- P            (c) T-s 

30. In a Mollier diagram the slope of an isobar is given by 
31. An ideal gas, is compressed in a perfectly insulated compressor from 1 bar and T=25°C to a final pressure of 10 bar. What is the temperature of the gas exiting at 10 bars? = 1.280 
(a) 220°C        (b) –92.8°C     (c) –56.6°C

32. When water is vaporized to steam, the total amount of heat added is equal to ... 
(a) usteam – uwater              (b) hsteam – hwater (c) ssteam – swater               (d) hsteam 

33. The latent heat of vaporization of COat -40°F and 145.8 psia is 137.8 Btu / lbm. The specific volume of saturated vapor produced by vaporization is 0.6113 ft3/lbm. The enthalpy of saturated COvapor at 145.8 psia is 137.8 Btu/lbm. What is its internal energy? 
(a) 105.3 Btu/lbm. 1               (b) 21.3 Btu/lbm.        (c) Need more data. 

34. For a process carried reversibly the rate of entropy generation within the system would be zero only when 
(a) the process is isothermal
(b) the process is adiabatic
(c) for both isothermal and adiabatic process 

35. The ratio of Cp/Cfor molecular nitrogen is 
(a) 1.21            (b) 1.44           (c) 1.63 

36. For an ideal gas with C= 38 J/mol K, the value of is
(a) 1.44 (b) 1.28 (c) 1.62 
(d) none of the above. 
(d) None of the above. 

37. When water is boiling in a beaker open to atmosphere, the latent heat of evaporation to be supplied is equal to 
(a) difference in specific internal energies of steam and water
(b) difference in specific enthalpies of steam and water
(c) difference in specific entropies of steam and water
(d) all of the above are true 

38. An ideal gas with C= 30 kJ/kmol. K is heated in a double-pipe heat exchanger from 300K to 406 K at a constant pressure of 1 bar. The amount of heat (kJ/kmol) to be added 
(a) 5533           (b) 2299          (c) 3180           (d) None of the above. 

39. For the above heat exchanger problem , the heat supplied to the gas is equal to the increase in 
(a) Enthalpy                            (b) Internal energy
(c) Neither ‘a’ nor ‘b’             (d) Need more data. 

40. A compressor with a cooling jacket compresses air from 1 bar to 50 bar at a constant temperature of 406K. The difference in enthalpy (kJ/mol) between the inlet and outlet gas (C= 30 J/mol.K) is 
(a) 0                                                     (b) 13.20                    
(c) Neither ‘a’ or ‘b’
(d) Problem not completely defined.
.
41. For the above compressor problem, the amount of heat (kJ/mol) removed by the cooling jacket is 
(a) 0                                         (b) 13.20
(c) Neither ‘a’ or ‘b’.              (d) Problem not completely defined. 

42. In an insulated constant volume reactor, nitrogen and hydrogen combine to form ammonia at an elevated temperature and pressure. Which of the following state variables remains constant during reaction? 
(a) Enthalpy. (b) Internal energy. (c) Entropy. (d) None of the above. 

43. Air is compressed adiabatically from 1 atm., 25°C to 10 atm. What is the exit temperature (0C ) of air assuming it to be ideal (Cp = 38 J/mol.K)? 
(a) 25               (b) 327            (c) – 25            (d) 220 

44. Which of the following may be assumed as an isentropic process ? 
(a) steam flow in a smooth well designed converging nozzle
(b) heating of water by injecting of live steam through a diverging nozzle (c) steam leaking through a partially opened valve
(d) mixing of sugar in water 

45. In h-s diagram the dome shaped region is for 
(a) vapor only
(b) liquid only
(c) vapor-liquid mixture
(d) super heated vapor. 

46. For pure liquid methanol, how many state variables are required to completely define the system 
(a) 1                 (b) 2                (c) 3                 (d) 4 

47. Compressed air throttled through a needle valve to atmospheric pressure. The throttling process is 
(a) Isenthalpic                         (b) Isentropic              (c) Isobaric                  (d) Isothermal. 

48. During a change of state, the change in which of the following state variable is equal to zero? 
(a) specific enthalpy
(b) specific entropy
(c) specific internal energy
(d) molar Gibbs free energy 

49. Melting of ice result in an 
(a) Increases in entropy
(b) Decreases in entropy
(c) Isentropic process
(d) None of these

50. The triple point of most fluids is close to 
(a) Boiling point
(b) Melting point

(c) Critical point. 

52. At the triple point of iodine (112.9°C and 11.57 kPa) the heat of fusion is 15.38 kJ/mol while the heat of sublimation is 59.8 kJ/mol. What is the latent heat of vaporization (kJ/mol)? 
(a) 44.5                        (b) 75.1            (c) 22.3                       (d) 19.76 

53. For estimating the thermodynamic properties of ethane at 10 atm pressure which of the following equations of state would you recommend? 
(a) Ideal gas                            (b) van der Waal        
(c) Peng – Robinson               (d) None of the above. 

54. The law of corresponding states is that all fluids at... 
(a) Same critical temperature and pressure will have the same critical volume
(b) Same reduced temperature and pressure will have the same reduced volume
(c) Same temperature and pressure will have the same specific volume
(d) None of these 

58. Compressibility factor (Z) of an ideal gas is 
(a) = 1 at all temperature and pressure.
(b) > 1 at all temperature and pressure.
(c) < 1 at all temperature and pressure.
(d) = 0 at all temperature and pressure. 

59. The compressibility factor of a gas is equal to 
(a) ratio for pressure of a real gas to its vapour pressure at the same temperature
(b) ratio of pressure of a real gas its critical pressure
(c) ratio of molar volume of real gas to that of an ideal gas at the same temperature and pressure 

60. Critical pressure of a substance is defined as 
(a) the pressure at which saturated liquid and vapour are in equilibrium
(b) the pressure at which an azeotrope is formed when mixed with steam
(c) the pressure above which the state of a substance may not be distinguished between liquid and vapour 

61. At the critical point which of the following criteria is not valid? 
(a) T= Tv                  (b) g= gv                   (c) s= sv                    (d) none of the above 

62. Critical compressibility factor of a real gas is the value of compressibility factor at 
(a) Critical temperature and pressure (TC, PC). 
(b) When the compressibility factor becomes unity
(c) When the compressibility factor becomes infinite
(d) None of these. 

63. Critical compressibility factor for permanent gases (N2, O2, etc) is approximately equal to ... 
(a) 0.28            (b) 0.35           (c) 1                 (d) None of these. 

64. At a reduced temperature of 1.10 and reduced pressure of 2.0 the compressibility factor for ethane is 0.42. What is the value compressibility factor for methane at the same reduced temperature and pressure ? 
(a) < 0.42                    (b) 0.42                       (c) > 0.42        (d) Need additional data. 

65. The value of compressibility factor (Z) is always less than or equal to unity. 
(a) True.          (b) False. 

66. The critical compressibility factor predicted by the van-der-Waal equation of state will be 
(a) Same for all gases and is equal to unity
(b) Same for all gases but not equal to unity 

(c) Different for different gases but is always greater than zero and less than unity 
(d) Different for different gases , actual value depends on the values of a and b (van-der Waal’s constants) 

67. The cubic equation of state can be represented as zaZbZ + = 0, where z is the compressibility factor. For CHat one particular temperature and pressure, cubic equation of state has one real root and two imaginary roots, therefore the state of the substance is 
(a) Mixture of liquid and vapor
(b) Either liquid or vapor but not a mixture
(c) Impossible to have imaginary roots for a physically meaningful state of the substance
(d) liquid 

68. The P-v isotherm of a real gas goes through an inflexion at the... 
(a) Critical pressure                (b) Vapor pressure of the liquid        
(c) triple point                         (d) all of the above 

70. Van-der Waal’s equation of state improved over the ideal gas equation of state with the following assumptions 
(a) infinitesimal molecular volume
(b) no inter molecular force
(c) both (a) and (b)
(d) none of the above. 

71. The ideal gas equation of state can predict the transition from the liquid state to vapor state of a substance 
(a) true            (b) false 

72. The critical compressibility factor predicted by the van-der equation of state is 
(a) 1.0              (b) 0.375                     (c) 0.27            (d) none of the above. 

73. The critical compressibility factor predicted by the ideal gas equation of state is 
(a) 1.0              (b) 0.375         (c) 0                 (d) none of the above. 

74. Critical compressibility factor for most real gases vary between 
(a) 0.23- 0.31              (b) 0.37 – 0.72            (c) 0.15 – 0.21 

75. The critical compressibility factor value for water is 
(a) 0.23            (b) 0.35           (c) 1.0              (d) 0 

76. Z(T= 1.20, P= 2.0) for N= 0.6. What would be the value of Z(T= 1.20, P= 2.0) O2
(a) >0.6           (b) <0.6           (c) =0.6           (d) Need additional data. 

For the following problems use the Steam Table 
77. When saturated liquid water is heated to form saturated steam at 101.3 kPa which of the following is TRUE? 
(a) Δ h = 0       (b) Δ g = 0       (c) Δ s = 0       (d) Δ u = 0 

78. Medium pressure steam is 
(a) 0-5 psig      (b) 5-15 psig              (c) > 15 psig. 

79. In a piston –cylinder apparatus, saturated steam at 1 atm is compressed to 5 atm, saturation temperature 
(a) T page4image58226704152°(C)           (b) T = 56°C               (c) T = 400° C             (d) T = 98° 

80. Steam at 1 atm. has an entropy = 6.619 kJ / kg.K. This steam is ... 
(a) Saturated steam.                (b) Super heated steam.
(c) Wet steam.                         (d) None of these. 

81. At 1 atm pressure the enthalpy of evaporation of steam (DH) is 2258 kJ/kg . At P = 5 atm, T = 151.58° C, DH (kJ/kg) is 
(a) < 2258                   (b) > 2258                   (c) =2258        (d) cannot be predicted. 

82. For saturated steam at 1 atm, T= 100° C the entropy of evaporation of steam (DS) is 6.0568 kJ/kg. Therefore, for saturated steam at 5 atm, T= 151.58° C, DS is 
(a) 4.9606                    (b) 6.5029                   (c) 6.0568        (d) cannot be predicted 

83. For saturated steam at 10 atm, T= 179.91° C, hsteam = 2778.1 kJ/kg.. If this steam is superheated to 500°C in a furnace at constant pressure, hsteam (kJ/kg) 
(a) 3478.5                    (b) 2606.4                   (c) 2778.1        (d) can not be predicted 

84. Steam at 400 bar and 500° C is throttled through an adiabatic pressure relief valve to atmospheric pressure. What is the temperature of steam after expansion? 
(a) 600°C        (b) 212°C        (c) 350°C        (d) can not be predicted. 

85. 98% quality of wet steam means 
(a) 0.02 kg water/kg steam-water mixture
(b) 0.98 kg water/kg steam-water-mixture
(c) 0.02 kg steam/kg steam-water mixture
(d) 0.98 kg water/kg of steam. 

86. Steam at 500 bar and 600 0C undergoes J-T expansion to 1 atm. What would be the temperature of steam after expansion ? Assume steam to be an ideal gas . 
(a) < 6000C     (b) 6000C        (c) > 6000

87. The enthalpy (kJ/kg) of steam at 400 bar and 500 0C is 
(a) 536             (b) 3900          (c) 2900           (d) 5300 

88. The temperature (0C) of saturated steam at 5 bar is 
(a) 253.2
(b) 151.8
(c) 102.7
(d) need more data. 

89. The enthalpy of steam (kJ/kg) at 10 atm and a degree of super heat of 320 0C is 
(a) 3478.5                    (b) 2606.4
(c) 2778.1                    (d) 433.3 

90. Steam at 400 bar and 500 0C is 
(a) saturated                            (b) super heated
(c) wet                                     (d) none of the above. 

91. For pure benzene vapor how many state variables must be defined for complete thermodynamic definition of the system? 
(a) 1(pressure or temperature)
(b) 2(pressure and temperature)
(c) 3(pressure, temperature and specific enthalpy) 

92. Compressed air at a high pressure is steadily and continuously exhausted through a pressure reducing value (Joule- Thomson Expansion). The J-T expansion is an ------------ process 
(a) Isenthalpic (b) Isothermal (c) Isobaric (d) isochoric 

93. For an ideal gas , the Joule – Thompson coefficient is always 
(a) > 0 (b) < 0 (c) = 0 (d) Depends on upstream and down stream pressure. 

94. The Joule – Thompson expansion coefficient (m) is defined as... 
page5image58343840page5image58344048page5image58344256page5image58344672

95. For an ideal gas, Joule Thompson expansion would always result 
(a) Increase in temperature (b) Decrease in temperature (c) Temperature remains unchanged 

96. An ideal gas at 35 bar , 230 0C is throttled adiabatically to 5 bar. What is the change in specific entropy (J/mol.K) ? 
(a) 0 (b) 32.39 (c) 0.587 (d) 103.77 

97. A steady stream containing 2% NaOH solution is entering a closed vessel. The overall mass balance equation is 
98. Chemical potential is an 
(a) Extensive property. (b) Intensive property. 

99. For a multi component system, chemical potential is equivalent to 
(a) Molal concentration difference.
(b) Molar free energy of the pure compounds.
(c) Partial molar free energy.
(d) Change in molar free energy due to phase change. 

100. The chemical potential of a species is an ideal solution depends on 
(a) Temperature. (b) Pressure. (c) Composition of solution (d) All of these. 

102. At constant temperature and pressure, for a pure substance the ratio of specific Gibbs free energy to the chemical potential is equal to 
(a) Zero. (b) Unity. (c) infinity. (d) < 0 

104. The Clapeyron equation 
(a) VLE(vapour liquid equilibrium only)
(b) SLE (Solid-liquid equilibrium only)
(c) SVE (Solid-vapour equilibrium only)
(d) Equilibrium between any two coexisting phases 

105. TheClausius-Clapyeron equation 
(a) VLE(vapour liquid equilibrium only)
(b) SLE (Solid-liquid equilibrium only)
(c) SVE (Solid-vapour equilibrium only)
(d) Equilibrium between any two coexisting phases 

106. The SI unit of fugacity is 
(a) kPa (b) kJ/kmol (c) kJ/kmol. K 

108. Raoults law applies to 
(a) Any liquid solution. (b) Ideal liquid solutions only. (c) Non-ideal liquid solutions. (d) Ideal gas mixture.

109. Which of the following assumption are inherent in Clausius – Clapeyron equation? 
(a) Specific molar volume of the liquid is very small compared to specific molar volume of the gas and as a result can be neglected
(b) Saturated vapor obeys ideal gas law.
(c) The molar heat of vaporization is independent of temperature. 

(d) All of the above 

110. Which of the following plots is expected to be linear? 
(a) lnpvap vs. 1/T           (b) lnpvap vs. T 
(c) p
vap vs. lnT              (d) pvap vs. ln (1/T) 
pvap is the vapor pressure of the liquid 

111. Antoine’s equation is generally valid in the pressure. 
(a) 1 – 200 kPa.
(b) 1 – 2 MPa. 

(c) at all pressures 

112. As water is heated to steam, the value of specific heat of the mixture is 
(a) 0 (b) 1 (c) (d) None of these.

113. During a phase change which of the following state variable is continuous and remains unchanged at the transition point. 
(a) Specific enthalpy (b) Specific entropy (c) Specific Gibbs free energy (d) molar volume 

114. A phase is defined as 
(a) a completely homogeneous and uniform state of matter
(b) a state of matter, which may not be homogeneous but consists of a single component
(c) a multicomponent state of matter, which may be wither homogenous or heterogeneous 

115. The fugacity of a solid is approximately equal to... 
(a) 1                 (b) 0                 (c)a

116. What is the change fugacity when a saturated liquid on heating is converted to saturated vapor?(a) 0                 (b) 1                 (c)a

117. The Poynting correction factor is used for calculation of fugacity of a liquid. The factor can be neglected if 
(a) System pressure is close to vapor pressure at system temperature.
(b) System pressure is very small compared to the vapor pressure at system temperature.
(c) System pressure is very large compared to vapor pressure at system temperature.
(d) None of above. 

118. Definition of fugacity ? 

119. The fugacity as defined in the above question is valid only for 
(a) Solid (b) Liquid (c) Gas (d) All states ( solid, liquid and gas ) 

120. For mixture of ideal gases , which of the following statements is NOT TRUE ? 
(a) partial molar volume of a species in the mixture is equal to the specific volume at the same temperature and pressure 
(b) partial molar enthalpy of a species in the mixture is equal to the specific enthalpy at the same temperature and pressure 
(c)chemical potential of a species in the mixture is equal to the molar Gibbs free energy at the same temperature and pressure 
(d)partial molar entropy of a species in the mixture is equal to the specific entropy at the same temperature and pressure 

121. For an ideal gas 
(a) fugacity is equal to pressure
(b) fugacity coefficient is equal to pressure (c) fugacity is always equal to 1

122. For a real gas at very low pressure 
(a) f » P
(b) 
f » 
(c) f » 
(d) all of the above 

123. In an ideal gas mixture, the fugacity of a component in the mixture is equal to 
(a) Mole fraction (b) Total pressure (c) Partial pressure (d) Chemical potential 

125. Fugacity and pressure are numerically equal when a gas 
(a) In standard state. (b) At high pressure. (c) At low pressure. 

126. The Gibbs Duhem equation is applicable for 
(a) molar Gibbs free energy ONLY 
(b) molar Gibbs free energy and excess Gibbs free energy ONLY
(c)chemical potential, molar Gibbs free energy and excess Gibbs free energy ONLY
(d) any partial molar property 

128. What is the change in fugacity when a saturated liquid on heating is converted to saturated vapour? 
(a) unity            (b) infinity        (c) 0 

130. For a cyclic process which of the following statement is true? 
(a) Only mechanical energy can be completely converted to thermal energy
(b) Only thermal energy can be converted completely to mechanical energy 
(c) Both (a) & (b) are true
(d) Both (a) & (b) are false. 

132. Match the following schematic representations 
(i) Refrigeration cycle
(ii) Heat engine
(iii) Heat pump
(iv) Thermodynamically not possible 

133. For a heat pump the coefficient of performance is defined as 
134. An engine receives heat at 700°F and rejects it to an environment at 180°F. What is the maximum thermo dynamic efficiency? 
(a) 100%                       (b) 44%
(c) 67%                        (d) Depends on construction of engine. 

135. The inside of a home is to be maintained at 22°C with a heat pump , while the outside temperature in the winter 2°C. Calculate the amount the energy requires for the heat pump? 
(a) 4.18 X 10kJ
(b) 1.20 X 10
kJ
(c) 6.78 X 10
kJ
(d) Need additional data 

136. Two refrigerators operate in reverse Rankine cycle rejecting the same amount if heat to a high temperature reservoir. The heat is pumped in both cases to large reservoir maintained at 300 K. First refrigerator (I) pumps heat from a heat source at 250 K while the second refrigerator (II) pumps heat from another heat source at 275 K. The ratio of energy supplied to the two refrigerators (WI/WII ) is 
(a) 1.0 (b) 2.0 (c) 0.5 (d) 0.91 

137. When two ideal gases are mixed the change in molar enthalpy is equal to 
(a) Zero. (b) Unity. (c) 0.5.
(d) Zero or non-zero depending on the property change being considered.

138. Pure component molar volume is equal to partial molar volume in a binary mixture 
(a) Always false. (b) Always true. (c) True only for a mixture of ideal gases. (d) all of the above 

140. One-constant model for estimation of activity coefficients of species in a binary liquid mixture is given by ? 

141. The activity coefficient of benzene in a benzene toluene mixture can be assumed to be equal to 
(a) vapour pressure of benzene
(b) critical temperature of benzene
(c) mole fraction of benzene in the mixture
(d) unity 

142. The partial pressure ( p1) of a species in a gas mixture is defined as the mole fraction of the species (y1) and the total pressure of the system ( p= yP). This definition is valid for 
(a) Ideal gas mixture only
(b) Non-ideal gas mixture only
(c) Both ideal and non-ideal gas mixtures. 

143. For an ideal solution which of the following equations is NOT TRUE 
(a) partial molar enthalpy of a species is equal to its pure molar enthalpy
(b) partial molar entropy of a species is equal to its pure molar entropy
(c)chemical potential of a species is equals pure molar Gibbs free energy
(d) none of the above 

144. A mixture of two ideal gases forms an ideal solution 
(a) Always true.
(b) Always false.
(c) May be true or false depending on the mixing conditions. 

145. A mixture of ideal gases is an ideal solution 
(a) Never.
(b) Only at low pressure.
(c) Only at low pressure and temperature well above critical point.
(d) Always. 

146. The reference state for molecular oxygen where the values of enthalpy and specific Gibb’s free energy are set equal to zero is 
(a) 25°C and 1.013 bar (b) 0°C and 1.013 bar (c) 373 K and 101 kPa 

147. For the reaction H+ 1⁄2 O= H2O, what is the value of the stochiometric coefficient O2?
(a) 1⁄2 (b) – 1⁄2 (c) 1 (d) 2 

148. For the reaction N+ O= 2 NO when the molar extent of reaction for N= 0.5, what is the value of molar extent of reaction for H2
(a) 0.5 (b) 1.0 (c) 0.25 

149. At a particular instant, the molar extent of reaction (x) calculated on the basis of moles of His 0.3. What would be the value of ‘x’ if calculated on the basis of moles of N2
(a) 0.1 (b) 0.3 (c) 0.9 (d) 1.0 

150. The molar extent of reaction is 
(a) Always greater than unity. (b) Always less than unity.
(c) Can be greater than, equal to, or less than unity. depending on the reaction stochiometry 

151. Pick the correct statement; For a chemical reaction 
(a)  total mass remains constant
(b)  total moles remain constant
(c) mass of each species remains constant
(d) moles of each species remain constant

153. At a constant temperature , for the ideal gas reaction   CO (g) + 2 H2 (g) = CH3OH (g); an increase in total pressure will result in 
 (a) increase in equilibrium yield of methanol
 (b) decrease in equilibrium yield of methanol
 (c) equilibrium yield will remain unchanged

154. For the gas phase reaction system (  N2 + O2 = 2 NO;  2 NO + O2 = 2NO2 ) , the degrees of freedom (F) at equilibrium are 

(a)  F =1                      (b)   F =2                     (c)  F =3                      (d) F =4

156. During the progress of a chemical reaction, the total Gibbs free energy (G) of the reacting system 
(a)  Remains constant at the initial value
(b)  Decreases continuously until the equilibrium is attained where ‘G’ is minimum.
(c) Increases continuously until equilibrium is attained where ‘G’ is maximum
 
159. For a particular reaction, the plot of ln K vs. 1/T is a straight line.  K is the equilibrium constant for the reaction.  This means that
(a)  Heat of reaction is zero
(b)  Heat of reaction is independent of temperature
(c) The specific heats of the reactants and products are identical
(d) Heat of reaction is a linear function of temperature
160. For a vapor-liquid mixture of water in equilibrium, any intensive property of the mixture (q =u, h, s, v) can be described as

(a)  q = x1q1 + (1-x1)q2                (b)  q = x1q2 + (1-x1)q1                (c) q = x1 (1-q1) + x2 (1-q2)

x1 is the mol fraction of the liquid in the mixture
q1 and q2 are the intensive properties of the liquid and vapor phase respectively
  
162. For a coexisting liquid and vapor phase equilibrium, the  phase rule gives us information on 
(a)  Degrees of freedom only.
(b)  Distribution of mass between the two phases.
(c) Both (a) & (b).
(d) None of these.

163. The Clapeyron equation can be used…
(a)  vapor – liquid equilibrium only
(b)  solid-liquid equilibrium only
(c) solid vapor equilibrium only
(d) equilibrium between any two coexisting phases
  
165. In an ideal plate of distillation tower a binary mixture of benzene and toluene liquid and vapor are in equilibrium.  Which of the following conditions do not apply for the phase equilibrium ? 

(a)  TL = Tv                                        (b)  PL = Pv                                        (c) sL = sv                                           (dmiL = miv

166. A paper reports VLE data for a binary hydrocarbon mixture.  Experimental data shows formation of an azeotrope and the author claims that the liquid behavior can be fitted well by a Regular solution model.  Which of the following conclusions may be made about the azeotrope? 
(a)  It must be  maximum boiling azeotrope
(b)  It must be a minimum boiling azeotrope
(c) There is no way to tell from the above statement whether it will be a maximum boiling or minimum boiling azeotrope
(d) The author’s claim about the Regular solution model is wrong as Regular solution model forbids formation of any azeotrope

167. For the vapour-liquid equilibrium of a binary mixture, the correct definition of the critical point is
(a)  The temperature above which the liquid phase does not exist and corresponding saturation pressure
(b)  The temperature to which the mixture must be heated for smooth transition from vapour to liquid phase without showing any phase transition and corresponding saturation pressure
(c) Meeting point of the bubble point and dew point line in a P_T diagram for the specific composition
(d) The temperature and pressure where the vapour liquid equilibrium ratio for both the components becomes simultaneously unity

168. The ‘T-xy’ diagram for an ideal binary mixture is affected by the change in pressure 
(a)  True.                     (b)  False.

169. The bubble point curve of a binary VLE system represents the state of saturated vapor 
(a)  True.                     (b)  False

170. The activity coefficient of benzene in a benzene- toluene mixture is 

(a)  Unity.                   (b)  Zero.        
(c) Infinity.                  (d) Depends on temperature and pressure

171. Liquid phase activity coefficients are generally less than zero for systems which exhibit negative deviations from Raoult's Law

(a) TRUE                    (b) FALSE

172. For a binary azeotrope

(a)  The dew point and bubble point curves are separated by the (P1Vap – P2Vap
(b)  P1Vap = P2Vap
(c) Both a and b
(d) Neither a nor b

173. The degrees of freedom for a binary azeotrope is 

(a) 0     (b) 1                 (c) 2                 (d) 3

174. To completely define a binary azeotrope, we need to define

(a)  Pressure only.
(b)  Both temperature and pressure.
(c) Temperature, pressure and composition in liquid phase only.
(d) Temperature, pressure and composition of both liquid and vapor phases.

175. For a binary system exhibiting negative deviation from Raoult’s law

(a)  Activity coefficients of both species are always less than zero.
(b)  Activity coefficients of both species are always less than unity.
(c) The gas phase mixture dos not obey Lewis – Randall law.

176. In an azeotropic mixture, the equilibrium vapor composition of the more volatile component is always
(a) Greater than the liquid composition of the less volatile component.
(b) Less than the liquid composition of the more volatile component.
(c) equal to the liquid composition of the less volatile component
(d) equal to liquid composition of the more volatile component

178. The upper consolute temperature for two partially miscible liquids is the temperature at which  
(a)  Two conjugate phases coexist.
(b)  A homogeneous (single phase solution is formed).
(c) The vapor pressures of the two phases become equal.
(d) None of these.

179. Distillation of a conjugate solution of two partially miscible liquids always results in 
(a)  The lower boiling compound as the final distillate.
(b)  The higher boiling compound as the final distillate.
(c) Depends on the relative proportions of the two existing phases.
(d) None of the above.

181. Which of the following liquid models will be unsuitable for representing a mixture of water and n – butanol?
(a)  NRTL                    (b)  WILSON                         
(c) UNIFAC                (d) UNIQUAC

182. Which of the models do not require binary or multicomponent  parameter?

(a)  WILSON                            (b)  UNIFAC              
(c) Regular Solution                 (d) UNIQUAC