The reaction A (l) → R(g) is allowed to reach equilibrium conditions in an autoclave. At equilibrium, there are two phases, one a pure liquid phase of A and the other a vapor phase of A, R and S. Initially A alone is present. The numbers of degrees of freedom are:
1
2
3
0
Correct Answer :
B. 2
Related Questions
An irreversible process
Is the analog of linear frictionless motion in machines
Is an idealised visualisation of behaviour of a system
Yields the maximum amount of work
Yields an amount of work less than that of a reversible process
For a thermodynamic system containing 'x' chemical species, the maximum number of phases that can co-exist at equilibrium is
x
x + 1
x + 2
x + 3
Number of phases in a colloidal system is:
1
2
3
4
Absolute zero temperature signifies the
Minimum temperature attainable
Temperature of the heat reservoir to which a Carnot engine rejects all the heat that is taken in
Temperature of the heat reservoir to which a Carnot engine rejects no heat
None of these
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Gibbs-Duhem
Van Laar
Gibbs-Helmholtz
Margules
In polytropic process (PVn = constant), if n = 1; it means a/an __________ process.
Adiabatic
Reversible
Isothermal
None of these
The unit of equilibrium constant of a chemical reaction is the same as that of
Molar concentration
Temperature
Internal energy
None of these
The necessary condition for phase equilibrium in a multiphase system of N components is that the
Chemical potentials of a given component should be equal in all phases
Chemical potentials of all components should be same in a particular phase
Sum of the chemical potentials of any given component in all the phases should be the same
None of these
When pressure is applied on the system, ice ↔ water, then
Equilibrium cannot be established
More ice will be formed
More water will be formed
Evaporation of water will take place
Gibbs free energy of mixing at constant pressure and temperature is always
0
∞
+ ve
- ve
For a constant pressure reversible process, the enthalpy change (ΔH) of the system is
Cv.dT
Cp.dT
∫ Cp.dT
∫ Cv.dT
Minimum number of phases that exists in a system is 1. Number of chemical species in a colloidal system is
1
2
3
4
The partial molar enthalpy of a component in an ideal binary gas mixture of composition Z, at a temperature T and pressure P, is a function only of
T
T and P
T, P and Z
T and Z
First law of thermodynamics is mathematically stated as
dQ = dE + dW
dQ = dE - dW
dE = dQ + dW
dW = dQ + dE
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Infinity
Minus infinity
Zero
None of these
The variation of heat of reaction with temperature at constant pressure is given by the __________ law.
Kelvin's
Antoines
Kirchoffs
None of these
A Carnot cycle consists of the following steps:
Two isothermal and two isentropic
Two isobaric and two isothermal
Two isochoric and two isobaric
Two isothermals and two isochoric
The change in Gibbs free energy for vaporisation of a pure substance is
Positive
Negative
Zero
May be positive or negative
Joule-Thomson effect i.e., a throttling process is a constant __________ process.
Entropy
Temperature
Internal energy
Enthalpy
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0.25
0.5
0.75
1
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2HI H2 + I2
N2O4 2NO2
2SO2 + O2 2SO3
None of these
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Two different gases behave similarly, if their reduced properties (i.e. P, V and T) are same
The surface of separation (i. e. the meniscus) between liquid and vapour phase disappears at the critical temperature
No gas can be liquefied above the critical temperature, howsoever high the pressure may be.
The molar heat of energy of gas at constant volume should be nearly constant (about 3 calories)
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Reversible and isothermal
Isothermal and irreversible
Reversible and adiabatic
Adiabatic and irreversible
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Internal energy
Enthalpy
Gibbs free energy
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-1.87
0
1.26
3.91
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Reverse Carnot cycle
Ordinary vapour-compression cycle
Vapour-compression process with a reversible expansion engine
Air refrigeration cycle
Heating of water under atmospheric pressure is an __________ process.
Isochoric
Isobaric
Adiabatic
Isothermal
The expression for the work done for a reversible polytropic process can be used to obtain the expression for work done for all processes, except reversible __________ process.
Isobaric
Isothermal
Adiabatic
None of these
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Expansion of a real gas
Reversible isothermal volume change
Heating of an ideal gas
Cooling of a real gas
Fugacity is a measure of the
Escaping tendencies of the same substance in different phases of a system
Relative volatility of a mixture of two miscible liquids
Behaviour of ideal gases
None of these