Pick out the undesirable property for a good refrigerant.
High thermal conductivity
Low freezing point
Large latent heat of vaporisation
High viscosity
Correct Answer :
D. High viscosity
Related Questions
Tea kept in a thermos flask is vigorously shaken. If the tea is considered as a system, then its temperature will
Increase
Decrease
Remain unchanged
First fall and then rise
Which is an example of closed system?
Air compressor
Liquid cooling system of an automobile
Boiler
None of these
Rotary lime kiln is an example of a/an __________ system.
Closed
Open
Isolated
Non-thermodynamic
The unit of fugacity is the same as that of the
Pressure
Temperature
Volume
Molar concentration
While dissolving a gas into a liquid at a constant temperature, the ratio of the concentration of the gas in the solution phase and in the gaseous phase is
Infinity
Unity
Constant
Negative
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
P1ACBP2P1
ACBB1A1A
ACBDA
ADBB1A1A
Solid and liquid phases of a substance are in equilibrium at the
Critical temperature
Melting point
Freezing point
Both (B) and (C)
For an ideal solution, the value of activity co-efficient is
0
1
< 1
> 1
__________ functions are exemplified by heat and work.
Path
Point
State
None of these
Critical compressibility factor for all substances
Are more or less constant (vary from 0.2 to 0.3)
Vary as square of the absolute temperature
Vary as square of the absolute pressure
None of these
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
6738.9
6753.5
7058.3
9000
The efficiency of an Otto engine compared to that of a diesel engine, for the same compression ratio will be
More
Less
Same
Data insufficient to predict
Joule-Thomson experiment is
Isobaric
Adiabatic
Isenthalpic
Both (B) & (C)
Boyle's law for gases states that
P ∝ 1/V, when temperature is constant
P ∝ 1/V, when temperature & mass of the gas remain constant
P ∝ V, at constant temperature & mass of the gas
P/V = constant, for any gas
As the entropy of the universe is increasing, day by day, the work producing capacity of a heat engine is
Not changed
Decreasing
Increasing
Data sufficient, can't be predicted
The adiabatic throttling process of a perfect gas is one of constant enthalpy
In which there is a temperature drop
Which is exemplified by a non-steady flow expansion
Which can be performed in a pipe with a constriction
In which there is an increase in temperature
Equation which relates pressure, volume and temperature of a gas is called the
Equation of state
Gibbs Duhem equation
Ideal gas equation
None of these
Heat pump
Accomplishes only space heating in winter
Accomplishes only space cooling in summer
Accomplishes both (A) and (B)
Works on Carnot cycle
Cv for an ideal gas
Does not depend upon temperature
Is independent of pressure only
Is independent of volume only
Is independent of both pressure and volume
Solubility of a substance which dissolves with an increase in volume and liberation of heat will be favoured by the
Low pressure and high temperature
Low pressure and low temperature
High pressure and low temperature
High pressure and high temperature
The equation, PV = nRT, is best obeyed by gases at
Low pressure & high temperature
High pressure & low temperature
Low pressure & low temperature
None of these
In the reaction, H2 +I2 2HI, addition of an inert gas will
Increase the partial pressure of H2
Increase the partial pressure of I2
Increase the total pressure and hence shift the equilibrium towards the right
Not affect the equilibrium conditions
Lowering of condenser temperature (keeping the evaporator temperature constant) in case of vapour compression refrigeration system results in
Increased COP
Same COP
Decreased COP
Increased or decreased COP; depending upon the type of refrigerant
Chemical engineering thermodynamics is concerned with the __________ in/of chemical processes.
Reaction mechanism
Calculation of rates
Energy transformation from one form to another
None of these
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
Which of the following processes cannot be made reversible even under ideal condition of operation?
Free expansion of a gas
Compression of air in a compressor
Expansion of steam in a turbine
All (A), (B) & (C)
Which of the following is an undesirable characteristic of a refrigerant?
It should be non-explosive
It should have a sub-atmospheric vapor pressure at the temperature in refrigerator coils
Its vapor pressure at the condenser temperature should be very high
None of these
Sound waves propagation in air exemplifies an __________ process.
Adiabatic
Isothermal
Isometric
None of these
Which of the following is not a reversible process?
Expansion of an ideal gas against constant pressure
Atmospheric pressure vaporisation of water at 100°C
Solution of NaCl in water at 50°C
None of these
For the reversible exothermic reaction, N2 + 3H2 2NH3, increase of pressure would
Shift the equilibrium towards right
Give higher yield of NH3
Both (B) and (C)
Neither (A) nor (B)