A. Gibbs-Duhem equation
B. Gibbs-Helmholtz equation
C. Third law of thermodynamics
D. Joule-Thomson effect
✅ The correct answer is option D.
Thermodynamics MCQs
192. 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.
193. 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.
194. 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.
195. 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.
196. 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.
197. When a system in equilibrium is subjected to a change in temperature, pressure or concentration, the equilibrium is displaced in a direction which tends to undo the effect of the change. This is called the
A. Le-Chatelier principle
B. Kopp’s rule
C. Law of corresponding state
D. Arrehenius hypothesis
✅ The correct answer is option A.
198. Trouton’s ratio is given by (where λb, = molal heat of vaporisation of a substance at its normal boiling point, kcal/kmol Tb = normal boiling point, °K )
A. λb/Tb
B. Tb/λb
C. √(λb/Tb)
D. √(Tb/λb)
✅ The correct answer is option A.
199. Grams of butane (C₄H₁₀) formed by the liquefaction of 448 litres of the gas (measured at (STP) would be
A. 580
B. 640
C. 1160
D. Data insufficient; can’t be computed
✅ The correct answer is option C.
200. Number of phases in a colloidal system are
A. 1
B. 2
C. 3
D. 4
✅ The correct answer is option B.