A. By throttling
B. By expansion in an engine
C. At constant pressure
D. None of these
✅ The correct answer is option A.
Thermodynamics MCQs
232. The relation connecting the fugacities of various components in a solution with one another and to composition at constant temperature and pressure is called the __________ equation.
A. Gibbs-Duhem
B. Van Laar
C. Gibbs-Helmholtz
D. Margules
✅ The correct answer is option A.
233. 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
✅ The correct answer is option A.
234. Extensive properties of a thermodynamic system depend upon the __________ of the system.
A. Specific volume
B. Temperature
C. Mass
D. Pressure
✅ The correct answer is option C.
235. The fusion of a crystalline solid at its melting point to form a liquid at the same temperature is accompanied by
A. Decrease in enthalpy corresponding to evolution of heat
B. Decrease of entropy
C. Increase in enthalpy corresponding to absorption of heat
D. No change in enthalpy
✅ The correct answer is option C.
236. 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
✅ The correct answer is option A.
237. Entropy is a/an
A. State function
B. Macroscopic property
C. Extensive property
D. None of these
✅ The correct answer is option D.
238. A gas can be liquified by pressure alone only, when its temperature is __________ its critical temperature.
A. Less than
B. More than
C. Equal to or higher than
D. Less than or equal to
✅ The correct answer is option D.
239. The variation of heat of reaction with temperature at constant pressure is given by the __________ law.
A. Kelvin’s
B. Antonie’s
C. Kirchoffs
D. None of these
✅ The correct answer is option C.
240. The number of degrees of freedom for an azeotropic mixture in a two component vapour-liquid equilibria is/are
A. Zero
B. One
C. Two
D. Three
✅ The correct answer is option B.