91. The Maxwell relation derived from the differential expression for the Helmholtz free energy (dA) is
A. (∂T/∂V)S = -(∂P/∂S)V
B. (∂S/∂P)T = -(∂V/∂T)P
C. (∂V/∂S)P = (∂T/∂P)S
D. (∂S/∂V)T = (∂P/∂T)V
✅ The correct answer is option D.
Thermodynamics MCQs
92. 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
✅ The correct answer is option A.
93. A nozzle is a device, which
A. Increases kinetic energy and decreases pressure
B. Reduces kinetic energy and increases pressure
C. Reduces both kinetic energy and pressure
D. Increases both kinetic energy and pressure
✅ The correct answer is option A.
94. 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
✅ The correct answer is option C.
95. Absolute zero temperature signifies the
A. Minimum temperature attainable
B. Temperature of the heat reservoir to which a Carnot engine rejects all the heat that is taken in
C. Temperature of the heat reservoir to which a Carnot engine rejects no heat
D. None of these
✅ The correct answer is option C.
96. In the equation, PVn = constant, if the value of n = 1, then it represents a reversible __________ process.
A. Isothermal
B. Isobaric
C. Polytropic
D. Adiabatic
✅ The correct answer is option A.
97. The chemical potential of any constituent of an ideal solution depends on the __________ of the solution.
A. Temperature
B. Pressure
C. Composition
D. All of the above
✅ The correct answer is option D.
98. Out of the following refrigeration cycles, which one has maximum COP?
A. Air cycle
B. Carnot cycle
C. Ordinary vapor compression cycle
D. Vapor compression with a reversible expansion engine
✅ The correct answer is option B.
99. Out of the following refrigration cycles, which one has the minimum COP (Co-efficient of performance)?
A. Air cycle
B. Carnot cycle
C. Ordinary vapour compression cycle
D. Vapour compression with a reversible expansion engine
✅ The correct answer is option A.
100. During Joule-Thomson expansion of gases
A. Enthalpy remains constant
B. Entropy remains constant
C. Temperature remains constant
D. None of these
✅ The correct answer is option A.