Practice Test: Question Set - 27
1. What happens in a reversible adiabatic expansion process?
- (A) Heating takes place
- (B) Cooling takes place
- (C) Pressure is constant
- (D) Temperature is constant
2. Keeping the pressure constant, to double the volume of a given mass of an ideal gas at 27°C, the temperature should be raised to __________ °C.
- (A) 270
- (B) 327
- (C) 300
- (D) 540
3. Free energy changes for two reaction mechanism 'X' and 'Y are respectively - 15 and - 5 units. It implies that ‘X’ is
- (A) Slower than Y
- (B) Faster than Y
- (C) Three times slower than Y
- (D) Three times faster than Y
4. The change in Gibbs free energy for vaporization of a pure substance is
- (A) Positive
- (B) Negative
- (C) Zero
- (D) May be positive or negative
5. The effect of changing the evaporator temperature on COP as compared to that of changing the condenser temperature (in vapor compression refrigeration system) is
- (A) Less pronounced
- (B) More pronounced
- (C) Equal
- (D) Data insufficient, can't be predicted
6. In any spontaneous process,
- (A) Only F decreases
- (B) Only A decreases
- (C) Both F and A decreases
- (D) Both F and A increase
7. Entropy change of the reaction, H2O (liquid) → H2O (gas), is termed as the enthalpy of
- (A) Solution
- (B) Vaporization
- (C) Formation
- (D) Sublimation
8. The partial pressure of each constituent present in an alloy is __________ the total vapor pressure exerted by the alloy.
- (A) Less than
- (B) Equal to
- (C) More than
- (D) Either (b) or (c); depends on the type of alloy
9. Free energy, fugacity and activity co-efficient are all affected by change in the temperature. The fugacity co-efficient of a gas at constant pressure __________with the increase of reduced temperature.
- (A) Decreases
- (B) Increases
- (C) Remains constant
- (D) Decreases logarithmically
10. In which of the following reaction equilibrium, the value of equilibrium constant Kp will be more than is Kc?
- (A) 2HI ⇌ H2 +
I2
- (B) N2O4 ⇌ 2NO2
- (C) 2SO2 + O2 ⇌ 2SO3
- (D) None of these
11. The principle applied in liquefaction of gases is
- (A) Adiabatic expansion
- (B) Joule-Thomson effect
- (C) Both (a) and (b)
- (D) Neither (a) nor (b)
12. Pick out the wrong statement.
- (A) Surface tension of a substance vanishes at critical point, as there
is no distinction between liquid and vapor phases at its critical point
- (B) Entropy of a system decreases with the evolution of heat
- (C) Change of internal energy is negative for exothermic reactions
- (D) The eccentric factor for all materials is always more than one
13. On opening the door of an operating refrigerator kept in a closed room, the temperature of the room will
- (A) Increase
- (B) Decrease
- (C) Remain same
- (D) Increase in summer and will decrease in winter
14. 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
15. __________ law of thermodynamics ascertains the direction of a particular spontaneous process.
- (A) Zeroth
- (B) First
- (C) Second
- (D) Third
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