371. The free energy change for a chemical reaction is given by (where, K = equilibrium constant)
A. RT lnK
B. -RT lnK
C. -R lnK
D. T lnK
✅ The correct answer is option B.
Thermodynamics MCQs
372. A Carnot cycle consists of the following steps :
A. Two isothermals and two isentropics
B. Two isobarics and two isothermals
C. Two isochorics and two isobarics
D. Two isothermals and two isochorics
✅ The correct answer is option A.
373. Which of the following has the minimum value of COP for a given refrigeration effect?
A. Reverse Carnot cycle
B. Ordinary vapour-compression cycle
C. Vapour-compression process with a reversible expansion engine
D. Air refrigeration cycle
✅ The correct answer is option D.
374. Boiling of liquid is accompanied with increase in the
A. Vapor pressure
B. Specific Gibbs free energy
C. Specific entropy
D. All of the above
✅ The correct answer is option A.
375. For a single component two phase mixture, the number of independent variable properties are
A. Two
B. One
C. Zero
D. Three
✅ The correct answer is option B.
376. At a given temperature, the volume of a gas dissolved in a solvent __________ with increase in pressure.
A. Increases
B. Decreases
C. Remains unchanged
D. May increase or decrease; depends on the gas
✅ The correct answer is option C.
377. In a working refrigerator, the value of COP is always
A. 0
B. < 0
C. < 1
D. > 1
✅ The correct answer is option D.
378. Which of the following non-flow reversible compression processes require maximum work?
A. Adiabatic process
B. Isothermal process
C. Isobaric process
D. All of the above
✅ The correct answer is option A.
379. The accentric factor of a materical, ‘ω’, is defined as ω = -log10(Prsat)Tr⁻¹ = 0.7, where, Prsat = reduced vapor pressure, Tr = reduced temperature. The value of accentric factor is always
A. > 2
B. < 1
C. > 1
D. < 3
✅ The correct answer is option B.
380. When a gas in a vessel expands, its internal energy decreases. The process involved is
A. Reversible
B. Irreversible
C. Isothermal
D. Adiabatic
✅ The correct answer is option A.