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What is the correct answer?

4

Gibbs free energy of mixing at constant pressure and temperature is always

A. 0

B.

C. + ve

D. - ve

Correct Answer :

D. - ve


Related Questions

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4

If the vapour pressure at two temperatures of a solid phase in equilibrium with its liquid phase are known, then the latent heat of fusion can be calculated by the

A. Maxwell's equation

B. Clausius-Clapeyron Equation

C. Van Laar equation

D. Nernst Heat Theorem

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4

__________ increases with increase in pressure.

A. The melting point of wax

B. The boiling point of a liquid

C. Both (A) and (B)

D. Neither (A) nor (B)

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4

For spontaneous changes in an isolated system (S = entropy)

A. ds = 0

B. ds <0

C. ds > 0

D. ds = Constant

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4

The four properties of a system viz. P, V, T, S are related by __________ equation.

A. Gibbs-Duhem

B. Gibbs-Helmholtz

C. Maxwell's

D. None of these

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4

Which of the following is a thermodynamic property of a system?

A. Concentration

B. Mass

C. Temperature

D. Entropy

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4

Change of heat content when one mole of compound is burnt in oxygen at constant pressure is called the

A. Calorific value

B. Heat of reaction

C. Heat of combustion

D. Heat of formation

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4

The compressibility factor for an ideal gas is 1. Its value for any other real gas is

A. 1

B. < 1

C. > 1

D. Either (B) or (C), depends on the nature of the gas

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4

The Maxwell relation derived from the differential expression for the Helmholtz free energy (dA) is

A. (∂T/∂V)S = - (∂P/∂S)V

B. (∂S/∂P)T = - (∂V/∂T)P

C. (∂V/∂S)P = (∂T/∂P)S

D. (∂S/∂V)T = (∂P/∂T)V

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4

1m3 of an ideal gas at 500 K and 1000 kPa expands reversibly to 5 times its initial volume in an insulated container. If the specific heat capacity (at constant pressure) of the gas is 21 J/mole . K, the final temperature will be

A. 35 K

B. 174 K

C. 274 K

D. 154 K

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4

Which is a state function?

A. Specific volume

B. Work

C. Pressure

D. Temperature

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4

Efficiency of a Carnot engine working between temperatures T1 and T2 (T1 < T) is

A. (T2 - T1)/T2

B. (T2 - T1)/T1

C. (T1 - T2)/T2

D. (T1 - T2)/T1

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4

Clausius-Clapeyron Equation gives accurate result, when the

A. Vapour pressure is relatively low and the temperature does not vary over wide limits

B. Vapour obeys the ideal gas law and the latent heat of vaporisation is constant

C. Volume in the liquid state is negligible compared with that in the vapour state

D. All (A), (B) and (C)

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4

After throttling, gas temperature

A. Decreases

B. Increases

C. Remain same

D. May increase or decrease; depends on the nature of the gas

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4

Steam undergoes isentropic expansion in a turbine from 5000 kPa and 400°C (entropy = 6.65 kJ/kg K) to 150 kPa) (entropy of saturated liquid = 1.4336 kJ/kg. K, entropy of saturated vapour = 7.2234 kJ/kg. K) The exit condition of steam is

A. Superheated vapour

B. Partially condensed vapour with quality of 0.9

C. Saturated vapour

D. Partially condensed vapour with quality of 0.1

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4

Critical solution temperature (or the consolute temperature) for partially miscible liquids (e.g., phenol-water) is the minimum temperature at which

A. A homogeneous solution (say of phenol water) is formed

B. Mutual solubility of the two liquids shows a decreasing trend

C. Two liquids are completely separated into two layers

D. None of these

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4

Critical compressibility factor for all substances

A. Are more or less constant (vary from 0.2 to 0.3)

B. Vary as square of the absolute temperature

C. Vary as square of the absolute pressure

D. None of these

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4

Pick out the correct statement.

A. Entropy and enthalpy are path functions

B. In a closed system, the energy can be exchanged with the surrounding, while matter cannot be exchanged

C. All the natural processes are reversible in nature

D. Work is a state function

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4

For water at 300°C, it has a vapour pressure 8592.7 kPa and fugacity 6738.9 kPa Under these conditions, one mole of water in liquid phase has a volume of 25.28 cm3 and that in vapour phase in 391.1 cm3.Fugacity of water (in kPa) at 9000 kPa will be

A. 6738.9

B. 6753.5

C. 7058.3

D. 9000

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4

Gibbs free energy per mole for a pure substance is equal to the

A. Latent heat of vaporisation

B. Chemical potential

C. Molal boiling point

D. Heat capacity

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4

In an ideal refrigeration cycle, the change in internal energy of the fluid is

A. +ve

B. -ve

C. 0

D. Either of the above three; depends on the nature of refrigerant

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4

The most important application of distribution law is in

A. Evaporation

B. Liquid extraction

C. Drying

D. Distillation

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4

Heating of water under atmospheric pressure is an __________ process.

A. Isochoric

B. Isobaric

C. Adiabatic

D. Isothermal

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4

Work done in an adiabatic process between two states depends on the

A. Rate of heat transmission

B. Initial state only

C. End states only

D. None of these

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4

Forward reaction will be favoured for the exothermic reaction, represented by CO + H2O CO2 + H2, by

A. Low temperature and high pressure

B. Low temperature and low pressure

C. High temperature and high pressure

D. High temperature and low pressure

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4

A domestic refrigerator has a/an __________ cooled condenser.

A. Water

B. Air

C. Evaporative

D. Gas

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4

Entropy of a substance remains constant during a/an __________ change.

A. Reversible isothermal

B. Irreversible isothermal

C. Reversible adiabatic

D. None of these

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4

Heat pump

A. Accomplishes only space heating in winter

B. Accomplishes only space cooling in summer

C. Accomplishes both (A) and (B)

D. Works on Carnot cycle

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4

When a gas in a vessel expands, its internal energy decreases. The process involved is

A. Reversible

B. Irreversible

C. Isothermal

D. Adiabatic

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4

At the absolute zero temperature, the entropy of every perfectly crystalline substance becomes zero. This follows from the

A. Third law of thermodynamics

B. Second law of thermodynamics

C. Nernst heat theorem

D. Maxwell's relations

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4

Which of the following is Clausius-Clapeyron Equation for vaporisation of an ideal gas under the condition that the molar volume of liquid is negligible compared to that of the vapor?

A. d ln p/dt = Hvap/RT2

B. d ln p/dt = RT2/Hvap

C. dp/dt = RT2/Hvap

D. dp/dt = Hvap/RT2