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4

# All gases except __________ shows a cooling effect during throttling process at atmospheric temperature and pressure.

Oxygen

Nitrogen

Air

Hydrogen

D. Hydrogen

### Related Questions

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4

# Melting of wax is accompanied with __________ in entropy.

Increase

Decrease

No change

None of these

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4

# In a homogeneous solution, the fugacity of a component depends upon the

Pressure

Composition

Temperature

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

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4

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

< 0

> 0

= 0

None of these

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4

# Pick out the correct statement.

Compression ratio of an Otto engine is comparatively higher than a diesel engine

Efficiency of an Otto engine is higher than that of a diesel engine for the same compression ratio

Otto engine efficiency decreases with the rise in compression ratio, due to decrease in work produced per quantity of heat

Diesel engine normally operates at lower compression ratio than an Otto engine for an equal output of work

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4

# The equation, Cp - Cv = R, is true for __________ gas.

No

Any real

Only ideal

Both (B) and (C)

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4

# The enthalpy change when ammonia gas is dissolved in water is called the heat of

Solution

Formation

Dilution

Combustion

What is the correct answer?

4

# On a P-V diagram of an ideal gas, suppose a reversible adiabatic line intersects a reversible isothermal line at point A. Then at a point A, the slope of the reversible adiabatic line (∂P/∂V)s and the slope of the reversible isothermal line (∂P/ ∂V)T are related as (where, y = Cp/Cv)

(∂P/∂V)S = (∂P/∂V)T

(∂P/∂V)S = [(∂P/∂V)T]Y

(∂P/∂V)S = y(∂P/∂V)T

(∂P/∂V)S = 1/y(∂P/∂V)T

What is the correct answer?

4

# In the equation PVn = constant, if the value of n = y = Cp/Cv, then it represents a reversible __________ process.

Isothermal

Isentropic

Polytropic

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4

# 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

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4

# The free energy change for a chemical reaction is given by (where, K = equilibrium constant)

RT ln K

-RT ln K

-R ln K

T ln K

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4

# At normal boiling point, molar entropy of vaporisation is __________ Joule/K°.mole.

72

92

142

192

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4

# For a cyclic process, a fixed ratio between heat and work

Always exists

May exist

Never exists

Is difficult to predict

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4

# The equation relating E, P, V and T which is true for all substances under all conditions is given by (∂E/∂V)T = T(∂P/∂T)H - P. This equation is called the

Maxwell's equation

Thermodynamic equation of state

Equation of state

Redlich-Kwong equation of state

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4

# In a reversible process

Tds = dE + dW

dE - dW = Tds

dW - dE = Tds

Tds - dW + dE >0

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4

# In jet refrigerators, the refrigerating fluid is practically always

Water

Ammonia

Freon

Brine

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4

# Which of the following identities can be most easily used to verify steam table data for superheated steam?

(∂T/∂V)S = (∂p/∂S)V

(∂T/∂P)S = (∂V/∂S)P

(∂P/∂T)V = (∂S/∂V)T

(∂V/∂T)P = -(∂S/∂P)T

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4

# When dilute aqueous solutions of two salts are mixed, the process is associated with

Decrease in temperature

Increase in temperature

No change in temperature

Change in temperature which is a function of composition

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4

# If an ideal solution is formed by mixing two pure liquids in any proportion, then the __________ of mixing is zero

Enthalpy

Volume

Both 'a' & 'b'

Neither 'a' nor 'b'

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4

# In an ideal gas mixture, fugacity of a species is equal to its

Vapor pressure

Partial pressure

Chemical potential

None of these

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4

# 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

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4

# At triple point (for one component system), vapour pressure of solid as compared to that of liquid will be

More

Less

Same

More or less; depending on the system

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4

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

0

50

100

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4

# A refrigeration cycle is the same as a __________ cycle,

Turbine

Heat engine

Reversed heat engine

None of these

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4

# Which of the following is not an intensive property?

Chemical potential

Surface tension

Heat capacity

None of these

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4

# In an isothermal process on an ideal gas, the pressure increases by 0.5 percent. The volume decreases by about __________ percent.

0.25

0.5

0.75

1

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4

# Which of the following is not an intensive property?

Molar heat capacity

Internal energy

Viscosity

None of these

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4

# The number of degrees of freedom for an azeotropic mixture in a two component vapour-liquid equilibria is/are

Zero

One

Two

Three

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4

# 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

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4

# Which of the following is a widely used refrigerant in vapour compression refrigeration system (using large centrifugal compressor)?

Freon

Liquid sulphur dioxide

Methyl chloride

Ammonia

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4

# The ratio of equilibrium constants (Kp2/Kp1) at two different temperatures is given by

(R/ΔH) (1/T1 - 1/T2)

(ΔH/R) (1/T1 - 1/T2)

(ΔH/R) (1/T2 - 1/T1)

(1/R) (1/T1 - 1/T2)