A. 1
B. < 1
C. > 1
D. Either (b) or (c), depends on the nature of the gas
✅ The correct answer is option D.
Thermodynamics MCQs
The adiabatic throttling process of a perfect gas is one of constant enthalpy
A. In which there is a temperature drop
B. Which is exemplified by a non-steady flow expansion
C. Which can be performed in a pipe with a constriction
D. In which there is an increase in temperature
✅ The correct answer is option C.
In reactions involving solids and liquids (where change in volume is negligible), the heat of reaction at constant pressure as compared to that at constant volume is
A. More
B. Less
C. Same
D. Unpredictable; depends on the particular reaction
✅ The correct answer is option C.
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.
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.
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.
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.
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.
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.
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.