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4

At the critical point of a substance

A. The surface tension vanishes

B. Liquid and vapour have the same density

C. There is no distinction between liquid and vapour phases

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

Correct Answer :

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


Related Questions

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4

Maximum work that could be secured by expanding the gas over a given pressure range is the __________ work.

A. Isothermal

B. Adiabatic

C. Isentropic

D. None of these

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4

Refrigeration capacity of a household refrigerator may be round about __________ tons.

A. 0.15

B. 1.5

C. 4.5

D. 6.5

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4

Third law of thermodynamics is helpful in

A. Prediction of the extent of a chemical reaction

B. Calculating absolute entropies of substances at different temperature

C. Evaluating entropy changes of chemical reaction

D. Both (B) and (C)

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4

Pick out the wrong statement.

A. Activity co-efficient is dimensionless.

B. In case of an ideal gas, the fugacity is equal to its pressure.

C. In a mixture of ideal gases, the fugacity of a component is equal to the partial pressure of the component.

D. The fugacity co-efficient is zero for an ideal gas

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4

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

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4

The theoretical minimum work required to separate one mole of a liquid mixture at 1 atm, containing 50 mole % each of n- heptane and noctane into pure compounds each at 1 atm is

A. -2 RT ln 0.5

B. -RT ln 0.5

C. 0.5 RT

D. 2 RT

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4

As the entropy of the universe is increasing, day by day, the work producing capacity of a heat engine is

A. Not changed

B. Decreasing

C. Increasing

D. Data sufficient, can't be predicted

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4

Fugacity is a measure of the

A. Escaping tendencies of the same substance in different phases of a system

B. Relative volatility of a mixture of two miscible liquids

C. Behaviour of ideal gases

D. None of these

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4

The change in Gibbs free energy for vaporisation of a pure substance is

A. Positive

B. Negative

C. Zero

D. May be positive or negative

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4

The specific heat of saturated water vapour at 100°C is

A.

B. -ve

C. 0

D. +ve

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4

Those solutions in which there is no volume change upon mixing the components in the liquid state and which, when diluted do not undergo any heat change (i.e. heat of dilution is zero), are called __________ solutions.

A. Ideal

B. Real

C. Isotonic

D. None of these

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4

Work done is a

A. Property of the system

B. Path function

C. Point function

D. State description of a system

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4

Pick out the wrong statement.

A. The chemical potential of a pure substance depends upon the temperature and pressure

B. The chemical potential of a component in a system is directly proportional to the escaping tendency of that component

C. The chemical potential of ith species (μi) in an ideal gas mixture approaches zero as the pressure or mole fraction (xi) tends to be zero at constant temperature

D. The chemical potential of species 'i' in the mixture (μi) is mathematically represented as,μi = ∂(nG)/∂ni]T,P,nj where, n, ni and nj respectively denote the total number of moles, moles of ith species and all mole numbers except ith species. 'G' is Gibbs molar free energy

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4

Which of the following is not an extensive property?

A. Free energy

B. Entropy

C. Refractive index

D. None of these

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4

In vapour compression refrigeration system, if the evaporator temperature and the condenser temperatures are -13°C and 37°C respectively, the Carnot COP will be

A. 5.2

B. 6.2

C. 0.168

D. Data insufficient, can't be found out

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4

A gas mixture of three components is brought in contact with a dispersion of an organic phase in water. The degree of freedom of the system is

A. 3

B. 4

C. 5

D. 6

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4

As the temperature is lowered towards the absolute zero, the value of the quantity (∂ΔF/∂T) approaches

A. Zero

B. Unity

C. Infinity

D. None of these

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4

For a constant volume process

A. dE = CpdT

B. dE = CvdT

C. dQ = dE + pdV

D. dW = pdV

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4

The relation connecting the fugacities of various components in a solution with one another and to composition at constant temperature and pressure is called the __________ equation.

A. Gibbs-Duhem

B. Van Laar

C. Gibbs-Helmholtz

D. Margules

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4

The Carnot co-efficient of performance (COP) of a domestic air conditioner compared to a household refrigerator is

A. Less

B. More

C. Same

D. Dependent on climatic conditions

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4

In the decomposition of PCl5 represented by, PCl5 PCl3 + Cl2, decrease in the pressure of the system will __________ the degree of dissociation of PCl5.

A. Increase

B. Decrease

C. Not alter

D. None of these

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4

Change of state namely evaporation condensation, freezing and melting is an __________ process.

A. Isothermal

B. Adiabatic

C. Isobaric

D. Isochoric

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4

The temperature at which a real gas obeys the ideal gas laws over a wide range of pressure is called the __________ temperature.

A. Critical

B. Boyle

C. Inversion

D. Reduced

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4

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

A. 0

B.

C. 50

D. 100

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4

Measurement of thermodynamic property of temperature is facilitated by __________ law of thermodynamics.

A. 1st

B. Zeroth

C. 3rd

D. None of these

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4

When a system is in equilibrium for all possible processes, the differential or finite change of entropy is

A. < 0

B. > 0

C. = 0

D. None of these

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4

A Carnot cycle consists of the following steps:

A. Two isothermal and two isentropic

B. Two isobaric and two isothermal

C. Two isochoric and two isobaric

D. Two isothermals and two isochoric

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4

Domestic refrigerator usually works on the __________ refrigeration cycle.

A. Carnot

B. Air

C. Absorption

D. vapour-ejection

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4

Pick out the correct statement.

A. A real gas on expansion in vacuum gets heated up

B. An ideal gas on expansion in vacuum gets cooled

C. An ideal gas on expansion in vacuum gets heated up

D. A real gas on expansion in vacuum cools down whereas ideal gas remains unaffected

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4

Pick out the wrong statement.

A. System (of partially miscible liquid pairs), in which the mutual solubility increases with rise in temperature, are said to possess an upper consolute temperature

B. Systems, in which the mutual solubility increases with decrease in temperature, are said to possess lower consolute temperature

C. Nicotine-water system shows both an upper as well as a lower consolute temperature, implying that they are partially miscible between these two limiting temperatures

D. None of these