161. With increase in compression ratio, the efficiency of the otto engine
A. Increases
B. Decreases
C. Remains constant
D. Increases linearly
✅ The correct answer is option A.
Thermodynamics MCQs
162. Second law of thermodynamics is concerned with the
A. Amount of energy transferred
B. Direction of energy transfer
C. Irreversible processes only
D. Non-cyclic processes only
✅ The correct answer is option B.
163. The most important application of distribution law is in
A. Evaporation
B. Liquid extraction
C. Drying
D. Distillation
✅ The correct answer is option B.
164. Mollier chart is a __________ plot.
A. Pressure vs enthalpy
B. Pressure vs volume
C. Enthalpy vs entropy
D. Temperature vs entropy
✅ The correct answer is option C.
165. A solid is transformed into vapour without going to the liquid phase at
A. Triple point
B. Boiling point
C. Below triple point
D. Always
✅ The correct answer is option A.
166. Partial molar free energy of an element A in solution is same as its
A. Chemical potential
B. Activity
C. Fugacity
D. Activity co-efficient
✅ The correct answer is option A.
167. Free energy change at equilibrium is
A. Zero
B. Positive
C. Negative
D. Indeterminate
✅ The correct answer is option A.
168. A cyclic engine exchanges heat with two reservoirs maintained at 100 and 300°C respectively. The maximum work (in J) that can be obtained from 1000 J of heat extracted from the hot reservoir is
A. 349
B. 651
C. 667
D. 1000
✅ The correct answer is option A.
169. Free energy change of mixing two liquid substances is a function of the
A. Concentration of the constituents only
B. Quantities of the constituents only
C. Temperature only
D. All of the above
✅ The correct answer is option D.
170. For the reversible exothermic reaction, N₂ + 3H₂ ⇋ 2NH₃, increase of pressure would
A. Shift the equilibrium towards right
B. Give higher yield of NH₃
C. Both B and C
D. Neither A nor B
✅ The correct answer is option C.