A. Its internal energy (U) decreases and its entropy (S) increases
B. U and S both decreases
C. U decreases but S is constant
D. U is constant but S decreases
✅ The correct answer is option B.
Thermodynamics MCQs
Claussius-Clayperon equation gives accurate result, when the
A. Vapour pressure is relatively low and the temperature does not vary over wide limits
B. Vapour obeys the ideal gas law and the latent heat of vaporisation is constant
C. Volume in the liquid state is negligible compared with that in the vapour state
D. All of the above
✅ The correct answer is option D.
The expression, nRT In P₁/P₂ , is for the____of an ideal gas.
A. Compressibility
B. Work done under adiabatic contition
C. Work done under isothermal condition
D. Co-efficient of thermal expansion
✅ The correct answer is option C.
If we increase the pressure on a substance (which is at its triple point), then the triple point
A. Increases
B. Decreases
C. Remains unchanged
D. May increase or decrease ; depends on the substance
✅ The correct answer is option C.
When a gas is expanded from high pressure region to low pressure region ; temper -ature change occurs. This phenomenon is related to the
A. Gibbs-Duhem equation
B. Gibbs-Helmholtz equation
C. Third law of thermodynamics
D. Joule-Thomson effect
✅ The correct answer is option D.
For a thermodynamic system containing ‘x’ chemical species, the maximum number of phases that can co-exist at equilibrium is
A. X
B. X + 1
C. X + 2
D. X + 3
✅ The correct answer is option C.
In a homogeneous solution, the activity co-efficient of a component depends upon the
A. Pressure
B. Composition
C. Temperature
D. All of the above
✅ The correct answer is option D.
If the molar heat capacities (Cp or Cv) of the reactants and products of a chemical reaction are identical, then, with the increase in temperature, the heat of reaction will
A. Increase
B. Decrease
C. Remain unaltered
D. Increase or decrease ; depends on the particular reaction
✅ The correct answer is option C.
What is the number of degree of freedom for a system of two miscible non-reacting species in vapor-liquid equilibrium forming an azeotrope?
A. 3
B. 2
C. 1
D. 0
✅ The correct answer is option C.
Compressibility factor for almost all the gases are approximately same at the same
A. Pressure and temperature
B. Reduced pressure and reduced temperature
C. Critical pressure and critical temperature
D. None of these
✅ The correct answer is option B.