For an ideal solution, the value of activity co-efficient is
0
1
< 1
> 1
Correct Answer :
B. 1
Related Questions
In any spontaneous process,
Only F decreases
Only A decreases
Both F and A decreases
Both F and A increase
Pick out the wrong statement.
A closed system does not permit exchange of mass with its surroundings but may permit exchange of energy.
An open system permits exchange of both mass and energy with its surroundings
The term microstate is used to characterise an individual, whereas macro-state is used to designate a group of micro-states with common characteristics
None of the above
If different processes are used to bring about the same chemical reaction, the enthalpy change is same for all of them. This is __________ law.
Hess's
Kirchoff's
Lavoisier and Laplace
None of these
At 60° C, vapour 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 vapour phase mole fractions of methanol are 0.1686 and 0.5714 respectively. Activity co-efficient of methanol is
1.572
1.9398
3.389
4.238
A large iceberg melts at the base, but not at the top, because of the reason that
Ice at the base contains impurities which lowers its melting point
Due to the high pressure at the base, its melting point reduces
The iceberg remains in a warmer condition at the base
All (A), (B) and (C)
At the absolute zero temperature, the entropy of every perfectly crystalline substance becomes zero. This follows from the
Third law of thermodynamics
Second law of thermodynamics
Nernst heat theorem
Maxwell's relations
A domestic refrigerator has a/an __________ cooled condenser.
Water
Air
Evaporative
Gas
Which of the following equations is obtained on combining 1st and 2nd law of thermodynamics, for a system of constant mass?
dE = Tds - PdV
dQ = CvdT + PdV
dQ = CpdT + Vdp
Tds = dE - PdV
Internal energy of an ideal gas
Increases with increase in pressure
Decreases with increase in temperature
Is independent of temperature
None of these
A refrigeration cycle is a reversed heat engine. Which of the following has the maximum value of the co-efficient of performance (COP) for a given refrigeration effect?
Vapor compression cycle using expansion valve
Air refrigeration cycle
Vapor compression cycle using expansion engine
Carnot refrigeration cycle
The unity of Planck's constant 'h' in the equation, E = hv is
J/s
J.S
J/kmol
kmol/J
Helmholtz free energy (A) is defined as
A = H - TS
A = E - TS
A = H + TS
None of these
A gas performs the maximum work, when it expands
Non-uniformly
Adiabatically
Isobarically
Isothermally
Gibbs free energy (G) is represented by, G = H - TS, whereas Helmholtz free energy, (A) is given by, A = E - TS. Which of the following is the Gibbs-Helmholtz equation?
[∂(G/T)/∂T] = - (H/T2)
[∂(A/T)/∂T]V = - E/T2
Both (A) and (B)
Neither (A) nor (B)
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
Superheated vapour
Partially condensed vapour with quality of 0.9
Saturated vapour
Partially condensed vapour with quality of 0.1
In an ideal refrigeration cycle, the change in internal energy of the fluid is
+ve
-ve
0
Either of the above three; depends on the nature of refrigerant
What is the ratio of adiabatic compressibility to isothermal compressibility?
1
< 1
> 1
>> 1
Gibbs-Duhem equation
States that n1dμ1 + n2dμ2 + ....njdμj = 0, for a system of definite composition at constant temperature and pressure
Applies only to binary systems
Finds no application in gas-liquid equilibria involved in distillation
None of these
In the equation, PVn = Constant, if the value of n = 0, then it represents a reversible __________ process.
Isobaric
Isothermal
Isentropic
Isometric
Free energy
Decreases in all spontaneous (or irreversible) processes
Change during a spontaneous process has a negative value
Remains unchanged in reversible processes carried at constant temperature and pressure
All (A), (B) and (C)
For an irreversible process involving only pressure-volume work
(dF)T, p <0
(dF)T, p = 0
(dF)T, p > 0
(dA)T, v >0
Gibbs free energy per mole for a pure substance is equal to the
Latent heat of vaporisation
Chemical potential
Molal boiling point
Heat capacity
Claude's liquefaction process employs the cooling of gases by
Expansion in an engine
Following a constant pressure cycle
Throttling
None of these
Kopp's rule is used to calculate the heat capacity of
Solids
Liquids
Gases
All (A), (B) & (C)
For multi-component multiple phases to be in equilibrium at the same pressure and temperature, the __________ of each component must be same in all phases.
Chemical potential
Fugacity
Both (A) and (B)
Neither (A) nor (B)
Which of the following is an extensive property of a system?
Heat capacity
Molal heat capacity
Pressure
Concentration
Critical temperature is defined as the temperature above which a gas will
Not liquify (barring exceptions)
Immediately liquify
Never liquify however high the pressure may be
None of these
__________ calorimeter is normally used for measuring the dryness fraction of steam, when it is very low.
Bucket
Throttling
Separating
A combination of separating & throttling
Entropy change of mixing two liquid substances depends upon the
Molar concentration
Quantity (i.e. number of moles)
Both (A) and (B)
Neither (A) nor (B)
Out of the following refrigeration cycles, which one has maximum COP?
Air cycle
Carnot cycle
Ordinary vapor compression cycle
Vapor compression with a reversible expansion engine