221. Which of the following is a widely used refrigerant in vapour compression refrigeration system (using large centrifugal compressor)?
A. Freon
B. Liquid sulphur dioxide
C. Methyl chloride
D. Ammonia
✅ The correct answer is option A.
Thermodynamics MCQs
222. Work done in an adiabatic process between two states depends on the
A. Rate of heat transmission
B. Initial state only
C. End states only
D. None of these
✅ The correct answer is option C.
223. One mole of nitrogen at 8 bar and 600 K is contained in a piston-cylinder arrangement. It is brought to 1 bar isothermally against a resisting pressure of 1 bar. The work done (in Joules) by the gas is
A. 30554
B. 10373
C. 4988.4
D. 4364.9
✅ The correct answer is option B.
224. Absorption/evolution of heat during conversion of a substance from one allotropic form to another is termed as the heat of
A. Sublimation
B. Fusion
C. Transition
D. Vaporisation
✅ The correct answer is option C.
225. 1m³ of an ideal gas at 500 K and 1000 kPa expands reversibly to 5 times its initial volume in an insulated container. If the specific heat capacity (at constant pressure) of the gas is 21 J/mole . K, the final temperature will be
A. 35 K
B. 174 K
C. 274 K
D. 154 K
✅ The correct answer is option C.
226. For an ideal gas, the enthalpy
A. Increases with rise in pressure
B. Decreases with rise in pressure
C. Is independent of pressure
D. Is a path function
✅ The correct answer is option C.
227. If heat contents of CH₄, C₂H₄ and C₃H₈ are -17.9, 12.5 and -24.8 kcal/mole respectively, than ΔH for the reaction CH₄(g) + C₂H₄(g) ⇋ C₃H₈(g) will be __________ Kcal.
A. -19.4
B. -30.2
C. 55.2
D. -55.2
✅ The correct answer is option A.
228. The value of Joule-Thomson co-efficient, in case where cooling occurs after the throttling process is
A. 0
B. ∞
C. +ve
D. -ve
✅ The correct answer is option C.
229. A refrigerator works on the principle of __________ law of thermodynamics.
A. Zeroth
B. First
C. Second
D. Third
✅ The correct answer is option C.
230. The chemical potential for a pure substance is __________ its partial molal free energy.
A. More than
B. Less than
C. Equal to
D. Not related to
✅ The correct answer is option C.