4

Enthalpy

Pressure

Entropy

None of these

C. Entropy

4

# 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

4

Minimum

Zero

Maximum

None of these

4

# When a gas is expanded from high pressure region to low pressure region; temperature change occurs. This phenomenon is related to the

Gibbs-Duhem equation

Gibbs-Helmholtz equation

Third law of thermodynamics

Joule-Thomson effect

4

# If the vapour pressure at two temperatures of a solid phase in equilibrium with its liquid phase are known, then the latent heat of fusion can be calculated by the

Maxwell's equation

Clausius-Clapeyron Equation

Van Laar equation

Nernst Heat Theorem

4

# Specific/molar Gibbs free energy for a pure substance does not change during

Sublimation

Vaporisation

Melting

Either (A), (B) or (C)

4

# Pick out the wrong statement.

Enthalpies of all elements in their standard states are assumed to be zero

Combustion reactions are never endothermic in nature

Heat of reaction at constant volume is equal to the change in internal energy

Clausius-Clapeyron equation is not applicable to melting process

4

# 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

4

0°C

273°C

100°C

-273°C

4

30554

10373

4988.4

4364.9

4

# In case of a close thermodynamic system, there is __________ across the boundaries.

No heat and mass transfer

No mass transfer but heat transfer

Mass and energy transfer

None of these

4

-19.4

-30.2

55.2

-55.2

4

H = E - PV

H = F - TS

H - E = PV

None of these

4

# For a given substance at a specified temperature, activity is __________ to fugacity.

Directly proportional

Inversely proportional

Equal

None of these

4

# __________ does not change during phase transformation processes like sublimation, melting & vaporisation.

Entropy

Gibbs free energy

Internal energy

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

4

0

1

2

3

4

# Pick out the correct statement.

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

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

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

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

4

Fusion

Vaporisation

Transition

None of these

4

# The main feature of Carnot refrigeration cycle is that, it

Does not need the addition of external work for its functioning

Transfers heat from high temperature to low temperature

Accomplishes the reverse effect of the heat engine

None of these

4

# Compressibility factor-reduced pressure plot on reduced co-ordinates facilitates

Use of only one graph for all gases

Covering of wide range

Easier plotting

More accurate plotting

4

Heat pump

Heat engine

Carnot engine

None of these

4

# Pick out the undesirable property for a good refrigerant.

High thermal conductivity

Low freezing point

Large latent heat of vaporisation

High viscosity

4

# 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)

4

Isothermal

Isometric

None of these

4

# A solid is transformed into vapour without going to the liquid phase at

Triple point

Boiling point

Below triple point

Always

4

+ve

0

-ve

4

Freon-12

Ethylene

Ammonia

Carbon dioxide

4

# Which of the following is an extensive property of a system?

Heat capacity

Molal heat capacity

Pressure

Concentration

4

# At a given temperature, the volume of a gas dissolved in a solvent __________ with increase in pressure.

Increases

Decreases

Remains unchanged

May increase or decrease; depends on the gas

4

50 kcal/hr

200 BTU/hr

200 BTU/minute

200 BTU/day