# Practice Test: Question Set - 23

**1. Which of the following has the least thermal efficiency?**

- (A) Steam engine

- (B) Carnot engine

- (C) Diesel engine

- (D) Otto engine

**2. The number of degrees of freedom for an azeotropic mixture in a two component vapor-liquid equilibria is/are**

- (A) Zero

- (B) One

- (C) Two

- (D) Three

**3. The point at which all the three (solid, liquid and gas) phases co-exist, is known as the __________ point.**

- (A) Freezing

- (B) Triple

- (C) Boiling

- (D) Boyle

**4. The freezing point of a liquid decreases when the pressure is increased, if the liquid __________ while freezing.**

- (A) Contracts

- (B) Expands

- (C) Does not change in volume

- (D) Either (a), (b) or (c)

**5. Specific volume of an ideal gas is**

- (A) Equal to its density

- (B) The reciprocal of its density

- (C) Proportional to pressure

- (D) None of these

**6. The compressibility factor of a gas is given by (where,**

*V*_{1}= actual volume of the gas*V*_{2}= gas volume predicted by ideal gas law)- (A)

*V*

_{1}/

*V*

_{2}

- (B)

*V*

_{2}/

*V*

_{1}

- (C)

*V*

_{1 }-

*V*

_{2}

- (D)

*V*

_{1}.

*V*

_{2}

**7. Dryness fraction of wet steam is defined as the ratio of mass of vapor in the mixture to the mass of mixture __________ calorimeter is not used for measuring the dryness fraction of steam.**

- (A) Bomb

- (B) Separating

- (C) Bucket

- (D) Throttling

**8. Molar heat capacity of water in equilibrium with ice at constant pressure is __________ Kcal/kg mole. °K**

- (A) 0

- (B) ∞

- (C) 50

- (D) 100

**9. The co-efficient of performance (COP) of a refrigerating system, which is its index of performance, is defined as the ratio of useful refrigeration to the net work. The units of __________ and COP are the same.**

- (A) Kinematic viscosity

- (B) Work

- (C) Temperature

- (D) None of these

**10. In any spontaneous process, the __________ free energy decreases.**

- (A) Helmholtz

- (B) Gibbs

- (C) Both ‘a’ & ‘b’

- (D) Neither 'a' nor 'b'

**11. The specific heat of saturated water vapor at 100°C is**

- (A) ∞

- (B) -ve

- (C) 0

- (D) +ve

**12. An isentropic process is carried out at constant**

- (A) Volume

- (B) Pressure

- (C) Temperature

- (D) All (a), (b) and (c)

**13. At 60° C, vapor pressure of methanol and water are 84.562 kPa and 19.953 kPa respectively. An aqueous solution of methanol at 60° C exerts a pressure of 39.223 kPa; the liquid phase and vapor phase mole fractions of methanol are 0.1686 and 0.5714 respectively. Activity co-efficient of methanol is**

- (A) 1.572

- (B) 1.9398

- (C) 3.389

- (D) 4.238

**14. Entropy is a measure of the __________ of a system.**

- (A) Disorder

- (B) Orderly behavior

- (C) Temperature changes only

- (D) None of these

**15. What is the value of Joule-Thomson co-efficient for an ideal gas?**

- (A) +ve

- (B) -ve

- (C) 0

- (D) ∞

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