A. More
B. Less
C. Same
D. Unpredictable; depends on the particular reaction
✅ The correct answer is option C.
Thermodynamics MCQs
452. In case of steady flow compression polytropic process (PVn = constant), the work done on air is the lowest, when
A. N = y = 1.4
B. N = 0
C. N = 1
D. N = 1.66
✅ The correct answer is option C.
453. Lowering of condenser temperature (keeping the evaporator temperature constant) in case of vapour compression refrigeration system results in
A. Increased COP
B. Same COP
C. Decreased COP
D. Increased or decreased COP ; depending upon the type of refrigerant
✅ The correct answer is option A.
454. Consider the reaction, C + O₂ ⇋ CO₂ ;ΔH = – 94 kcal. What will be the value of ΔH for the reaction CO₂ → C + O₂?
A. -94 kcal
B. + 94 kcal
C. > 94 kcal
D. < -94 kcal
✅ The correct answer is option B.
455. Fugacity and pressure are numerically not equal for the gases
A. At low temperature and high pressure
B. At standard state
C. Both A and B
D. In ideal state
✅ The correct answer is option C.
456. Henry’s law is closely obeyed by a gas, when its __________ is extremely high.
A. Pressure
B. Solubility
C. Temperature
D. None of these
✅ The correct answer is option D.
457. The change in Gibbs freee energy for vaporisation of a pure substance is
A. Positive
B. Negative
C. Zero
D. May be positive or negative
✅ The correct answer is option C.
458. Which of the following decreases with increase in pressure?
A. Melting point of ice
B. Melting point of wax
C. Boiling point of liquids
D. None of these
✅ The correct answer is option A.
459. The work done in isothermal compression compared to that in adiabatic compression will be
A. Less
B. More
C. Same
D. More or less depending upon the extent of work done
✅ The correct answer is option B.
460. Sublimation temperature of dry ice (solid CO₂) is __________ °C.
A. -273
B. 0
C. -78
D. 5
✅ The correct answer is option C.