4

-94 kcal

> -94 kcal

< - 94 kcal

Zero

D. Zero

4

# The gas law (PV = RT) is true for an __________ change.

Isothermal

Both (A) & (B)

Neither (A) nor (B)

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

# Pick out the wrong statement.

The conversion for a gas phase reaction increases with decrease in pressure, if there is an increase in volume accompanying the reaction

With increase in temperature, the equilibrium constant increases for an exothermic reaction

The equilibrium constant of a reaction depends upon temperature only

The conversion for a gas phase reaction increases with increase in pressure, if there is a decrease in volume accompanying the reaction

4

# Pick out the wrong statement.

The values of (∂P/∂V)T and (∂2P/∂V2)T are zero for a real gas at its critical point

Heat transferred is equal to the change in the enthalpy of the system, for a constant pressure, non-flow, mechanically reversible process

Thermal efficiency of a Carnot engine depends upon the properties of the working fluid besides the source & sink temperatures

During a reversible adiabatic process, the entropy of a substance remains constant

4

# Air-refrigeration cycle

Is the most efficient of all refrigeration cycles

Has very low efficiency

Requires relatively large quantities of air to achieve a significant amount of refrigeration

Both (B) and (C)

4

# Absolute zero temperature signifies the

Minimum temperature attainable

Temperature of the heat reservoir to which a Carnot engine rejects all the heat that is taken in

Temperature of the heat reservoir to which a Carnot engine rejects no heat

None of these

4

# When a gas is subjected to adiabatic expansion, it gets cooled due to

Decrease in velocity

Decrease in temperature

Decrease in kinetic energy

Energy spent in doing work

4

# Free energy changes for two reaction mechanism 'X' and 'Y are respectively - 15 and - 5 units. It implies that X is

Slower than Y

Faster than Y

Three times slower than Y

Three times faster than Y

4

# In an irreversible process

Tds = dE - dW = 0

dE - dW - Tds = 0

Tds - dE + dW < 0

Tds - dT + dW < 0

4

Zeroth

First

Second

Third

4

# Refrigerants commonly used for domestic refrigerators are

Ethyl chloride or methyl chloride

Freon-12

Propane

NH3 or CO2

4

# With increase in temperature, the atomic heat capacities of all solid elements

Increases

Decreases

Remains unchanged

Decreases linearly

4

0

+ve

-ve

4

# An ideal liquid refrigerant should

Not have a sub-atmospheric vapour pressure at the temperature in the refrigerator coils

Not have unduly high vapour pressure at the condenser temperature

Both (A) and (B)

Have low specific heat

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

349

651

667

1000

4

λb/Tb

Tb/λb

√(λb/Tb)

√(Tb/λb)

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

Ideal

Real

Isotonic

None of these

4

Zero

50%

Almost 100%

unpredictable

4

Zero

Positive

Negative

None of these

4

# If we increase the pressure on a substance (which is at its triple point), then the triple point

Increases

Decreases

Remains unchanged

May increase or decrease; depends on the substance

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

Molecular size

Volume

Pressure

Temperature

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

Isothermal

Isentropic

Isobaric

4

# The unit of fugacity is the same as that of the

Pressure

Temperature

Volume

Molar concentration

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)

4

Zero

One

Infinity

Negative