4

# Enthalpy changes over a constant pressure path are always zero for __________ gas.

Any

A perfect

An easily liquefiable

A real

B. A perfect

4

# For an ideal gas, the enthalpy

Increases with rise in pressure

Decreases with rise in pressure

Is independent of pressure

Is a path function

4

0°C

273°C

100°C

-273°C

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

# For the gaseous phase chemical reaction, C2H4(g) + H2O(g) ↔ C2H5OH(g), the equilibrium conversion does not depend on the

Steam to ethylene ratio

Temperature

Pressure

None of these

4

# Pick out the wrong statement.

A refrigeration cycle violates the second law of thermodynamics

Refrigeration cycle is normally represented by a temperature vs. entropy plot

In a refrigerator, work required decreases as the temperature of the refrigerator and the temperature at which heat is rejected increases

One ton of refrigeration is equivalent to the rate of heat absorption equal to 3.53 kW

4

CO2

H2

O2

N2

4

# Mollier diagram is a plot of

Temperature vs. enthalpy

Temperature vs. enthalpy

Entropy vs. enthalpy

Temperature vs. internal energy

4

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

Triple point

Boiling point

Below triple point

Always

4

# Third law of thermodynamics is helpful in

Prediction of the extent of a chemical reaction

Calculating absolute entropies of substances at different temperature

Evaluating entropy changes of chemical reaction

Both (B) and (C)

4

Entropy

Gibbs energy

Internal energy

Enthalpy

4

0

< 0

< 1

> 1

4

# After throttling, gas temperature

Decreases

Increases

Remain same

May increase or decrease; depends on the nature of the gas

4

-ve

0

+ve

4

30554

10373

4988.4

4364.9

4

# Mollier chart is a __________ plot.

Pressure vs. enthalpy

Pressure vs. volume

Enthalpy vs. entropy

Temperature vs. entropy

4

< 0

> 0

= 0

None of these

4

# Gibbs-Duhem equation relates composition in liquid phase and the __________ at constant temperature & pressure.

Fugacity

Partial pressure

Activity co-efficient

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

4

# Refrigeration cycle

Violates second law of thermodynamics

Involves transfer of heat from low temperature to high temperature

Both (A) and (B)

Neither (A) nor (B)

4

# When liquid and vapour phase of multi-component system are in equilibrium (at a given temperature and pressure), then chemical potential of each component is

Same in both the phases

Zero in both the phases

More in vapour phase

More in liquid phase

4

Zero

Positive

Negative

None of these

4

# Which of the following equations is used for the prediction of activity co-efficient from experiments?

Van Laar equation

Margules equation

Wilson's equation

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

4

√(2KT/m)

√(3KT/m)

√(6KT/m)

3KT/m

4

# 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

4

# __________ explains the equilibrium constant for any chemical reaction.

Henry's law

Law of mass action

Hess's law

None of these

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

4

Temperature

Pressure

Volume

Entropy

4

4 J

0

8 J

4

# Pick out the correct statement.

A real gas on expansion in vacuum gets heated up

An ideal gas on expansion in vacuum gets cooled

An ideal gas on expansion in vacuum gets heated up

A real gas on expansion in vacuum cools down whereas ideal gas remains unaffected

4

# Entropy of the system decreases, when

Snow melts into water

A gas expands spontaneously from high pressure to low pressure

Water is converted into ice

Both (B) & (C)