Thermodynamics for Chemical Mcqs - Set 2

1)   When a gas is subjected to adiabatic expansion, it gets cooled due to__________________?

a. Decrease in velocity
b. Decrease in temperature
c. Decrease in kinetic energy
d. Energy spent in doing work
Answer  Explanation 

ANSWER: Energy spent in doing work

Explanation:
No explanation is available for this question!


2)   Work done in case of free expansion is____________________?

a. Indeterminate
b. Zero
c. Negative
d. None of these
Answer  Explanation 

ANSWER: Zero

Explanation:
No explanation is available for this question!


3)   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  Explanation 

ANSWER: High T, low P

Explanation:
No explanation is available for this question!


4)   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  Explanation 

ANSWER: Remains unchanged

Explanation:
No explanation is available for this question!


5)   The molar excess Gibbs free energy, gE, for a binary liquid mixture at T and P is given by, (gE/RT) = A . x1. x2, where A is a constant. The corresponding equation for ln y1, where y1 is the activity co-efficient of component 1, is__________________?

a. A . x22
b. Ax1
c. Ax2
d. Ax12
Answer  Explanation 

ANSWER: A . x22

Explanation:
No explanation is available for this question!


6)   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  Explanation 

ANSWER: Temperature

Explanation:
No explanation is available for this question!


7)   The most important application of distribution law is in_____________________?

a. Evaporation
b. Liquid extraction
c. Drying
d. Distillation
Answer  Explanation 

ANSWER: Liquid extraction

Explanation:
No explanation is available for this question!


8)   Enthalpy changes over a constant pressure path are always zero for ______________ gas?

a. Any
b. A perfect
c. An easily liquefiable
d. A real
Answer  Explanation 

ANSWER: A perfect

Explanation:
No explanation is available for this question!


9)   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  Explanation 

ANSWER: Representing actual behaviour of real gases

Explanation:
No explanation is available for this question!


10)   During adiabatic expansion of gas___________________?

a. Pressure remains constant
b. Pressure is increased
c. Temperature remains constant
d. None of these
Answer  Explanation 

ANSWER: None of these

Explanation:
No explanation is available for this question!


11)   What is the degree of freedom for a system comprising liquid water equilibrium with its vapour ?

a. 0
b. 1
c. 2
d. 3
Answer  Explanation 

ANSWER: 1

Explanation:
No explanation is available for this question!


12)   In an ideal solution, the activity of a component equals its __________________?

a. Mole fraction
b. Fugacity at the same temperature and pressure
c. Partial pressure
d. None of these
Answer  Explanation 

ANSWER: Mole fraction

Explanation:
No explanation is available for this question!


13)   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  Explanation 

ANSWER: Adiabatic process

Explanation:
No explanation is available for this question!


14)   Pressure-enthalpy chart is useful in refrigeration. The change in internal energy of an ideal fluid used in ideal refrigeration cycle is_____________________?

a. Positive
b. Negative
c. Zero
d. Infinity
Answer  Explanation 

ANSWER: Zero

Explanation:
No explanation is available for this question!


15)   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 = Hvap/RT2
b. d ln p/dt = RT2/Hvap
c. dp/dt = RT2/Hvap
d. dp/dt = Hvap/RT2
Answer  Explanation 

ANSWER: d ln p/dt = Hvap/RT2

Explanation:
No explanation is available for this question!


16)   Cp – Cv = R is valid for ______________ gases?

a. Ideal
b. Very high pressure
c. Very low temperature
d. All of the above
Answer  Explanation 

ANSWER: Ideal

Explanation:
No explanation is available for this question!


17)   If two pure liquid constituents are mixed in any proportion to give an ideal solution, there is no change in____________________?

a. Volume
b. Enthalpy
c. Both A. & B
d. Neither A. nor B
Answer  Explanation 

ANSWER: Both A. & B

Explanation:
No explanation is available for this question!


18)   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  Explanation 

ANSWER: Departure from ideal solution behaviour

Explanation:
No explanation is available for this question!


19)   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  Explanation 

ANSWER: In ideal state

Explanation:
No explanation is available for this question!


20)   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  Explanation 

ANSWER: Value of absolute entropy

Explanation:
No explanation is available for this question!


21)   Clapeyron Equation deals with the____________________?

a. Rate of change of vapour pressure with temperature
b. Effect of an inert gas on vapour pressure
c. Calculation of ΔF for spontaneous phase change
d. Temperature dependence of heat of phase transition
Answer  Explanation 

ANSWER: Rate of change of vapour pressure with temperature

Explanation:
No explanation is available for this question!


22)   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  Explanation 

ANSWER: Is independent of pressure

Explanation:
No explanation is available for this question!


23)   Fugacity and pressure are numerically not equal for the gases__________________?

a. At low temperature and high pressure
b. At standard state
c. Both A. and B
d. In ideal state
Answer  Explanation 

ANSWER: Both A. and B

Explanation:
No explanation is available for this question!


24)   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  Explanation 

ANSWER: End states only

Explanation:
No explanation is available for this question!


25)   Which is an example of closed system ?

a. Air compressor
b. Liquid cooling system of an automobile
c. Boiler
d. None of these
Answer  Explanation 

ANSWER: Liquid cooling system of an automobile

Explanation:
No explanation is available for this question!


26)   For a reversible process involving only pressure-volume work____________________?

a. (dF)T, p 0
b. (dF)T, p = 0
c. (dA)T, v < 0
d. None of these
Answer  Explanation 

ANSWER: (dF)T, p = 0

Explanation:
No explanation is available for this question!


27)   Gibbs-Duhem equation relates composition in liquid phase and the _____________ at constant temperature & pressure?

a. Fugacity
b. Partial pressure
c. Activity co-efficient
d. All (A), (B), and (C)
Answer  Explanation 

ANSWER: All (A), (B), and (C)

Explanation:
No explanation is available for this question!


28)   A reasonably general expression for vapour-liquid phase equilibrium at low to moderate pressure is φi yi P = Yi xifi° where, Φ is a vapor fugacity component, Yi is the liquid activity coefficient and fi° is the fugacity of the pure component i. the Ki value (Yi = Ki xi) is therefore, in general a function of ______________________?

a. Temperature only
b. Temperature and pressure only
c. Temperature, pressure and liquid composition xi only
d. Temperature, pressure, liquid composition xi and vapour composition yi
Answer  Explanation 

ANSWER: Temperature, pressure and liquid composition xi only

Explanation:
No explanation is available for this question!


29)   The reaction A (l) → R(g) is allowed to reach equilibrium conditions in an autoclave. At equilibrium, there are two phases, one a pure liquid phase of A and the other a vapor phase of A, R and S. Initially A alone is present. The numbers of degrees of freedom are ?

a. 1
b. 2
c. 3
d. 0
Answer  Explanation 

ANSWER: 2

Explanation:
No explanation is available for this question!


30)   Air enters an adiabatic compressor at 300K. The exit temperature for a compression ratio of 3, assuming air to be an ideal gas (Y = Cp/Cv = 7/5) and the process to be reversible, is___________________?

a. 300 × (32/7)
b. 300 × (33/5)
c. 300 × (333/7)
d. 300 × (35/7)
Answer  Explanation 

ANSWER: 300 × (32/7)

Explanation:
No explanation is available for this question!