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What is the correct answer?

4

Activity co-efficient is a measure of the

A. Departure from ideal solution behaviour

B. Departure of gas phase from ideal gas law

C. Vapour pressure of liquid

D. None of these

Correct Answer :

A. Departure from ideal solution behaviour


Related Questions

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4

Gibbs free energy (F) is defined as

A. F = E - TS

B. F = H - TS

C. F = H + TS

D. F = E + TS

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4

Which of the following is not a reversible process?

A. Expansion of an ideal gas against constant pressure

B. Atmospheric pressure vaporisation of water at 100°C

C. Solution of NaCl in water at 50°C

D. None of these

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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

Gases are cooled in Joule-Thomson expansion, when it is __________ inversion temperature.

A. Below

B. At

C. Above

D. Either 'b' or 'c'

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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

A gas can be liquefied by pressure alone only, when its temperature is __________ its critical temperature.

A. Less than

B. More than

C. Equal to or higher than

D. Less than or equal to

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4

Refrigerants commonly used for domestic refrigerators are

A. Ethyl chloride or methyl chloride

B. Freon-12

C. Propane

D. NH3 or CO2

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4

A solute distributes itself between two nonmiscible solvents in contact with each other in such a way that, at a constant temperature, the ratio of its concentrations in two layers is constant, irrespective of its total amount. This is

A. The distribution law

B. Followed from Margules equation

C. A corollary of Henry's law

D. None of these

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4

Near their critical temperatures, all gases occupy volumes __________ that of the ideal gas.

A. Less than

B. Same as

C. More than

D. Half

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4

What is the value of maximum COP in case of absorption refrigeration, if refrigeration provided is at temperature, TR (where, T1 and T2 are source & surrounding temperatures respectively.)?

A. TR/(T2 - TR) × (T1 - T2)/T1

B. TR/(T2 - TR) × T1/(T1 - T2)

C. TR/(T1 - TR) × (T1 - T2)/T1

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

In a reversible chemical reaction (where, Δx = number of moles of products-number of moles of reactants)

A. Addition of inert gas favours the forward reaction, when Δx is positive

B. Pressure has no effect on equilibrium, when Δn = 0

C. Addition of inert gas has no effect on the equilibrium constant at constant volume for any value of Δx (+ ve, - ve) or zero)

D. All 'a', 'b' & 'c'

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4

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

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4

(∂T/∂P)H is the mathematical expression for

A. Specific heat at constant pressure (Cp)

B. Specific heat at constant volume (Cv)

C. Joule-Thompson co-efficient

D. None of these

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4

A thermodynamic system is taken from state A to B along ACB and is brought back to A along BDA as shown below in the P-V diagram. The net work done during the complete cycle is given by the area covered by

A. P1ACBP2P1

B. ACBB1A1A

C. ACBDA

D. ADBB1A1A

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4

The shape of T-S diagram for Carnot Cycle is a

A. Rectangle

B. Rhombus

C. Trapezoid

D. Circle

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4

In an ideal solution, the activity of a component equals its

A. Mole fraction

B. Fugacity at the same temperature and pressure

C. Partial pressure

D. None of these

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4

__________ explains the equilibrium constant for any chemical reaction.

A. Henry's law

B. Law of mass action

C. Hess's law

D. None of these

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4

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

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4

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

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4

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

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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

Pick out the correct statement.

A. The available energy in an isolated system for all irreversible (real) processes decreases

B. The efficiency of a Carnot engine increases, if the sink temperature is decreased

C. The reversible work for compression in non-flow process under isothermal condition is the change in Helmholtz free energy

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

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4

Chemical potential (an intensive property) of a substance is a force that drives the chemical system to equilibrium and is equal to its partial molar properties. The ratio of chemical potential to free energy of a pure substance at constant temperature and pressure is

A. 0

B. 1

C.

D. None of these

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4

To obtain integrated form of Clausius-Clapeyron equation, ln (P2/P1) = (ΔHV/R) (1/T1 - 1/T2) from the exact Clapeyron equation, it is assumed that the

A. Volume of the liquid phase is negligible compared to that of vapour phase

B. Vapour phase behaves as an ideal gas

C. Heat of vaporisation is independent of temperature

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

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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

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

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

Critical temperature is defined as the temperature above which a gas will

A. Not liquify (barring exceptions)

B. Immediately liquify

C. Never liquify however high the pressure may be

D. None of these

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4

With increase in reduced temperature, the fugacity co-efficient of a gas at constant reduced pressure

A. Increases

B. Decreases

C. Remain same

D. Decreases linearly