THERMODYNAMICS
KUMAR SHISHIR
THERMODYNAMICS
CHEMISTRY
ONE OR MORE THAN ONE CORRECT TYPE
1.
Which of the following statement(s) is/are correct :
Statement(a) : In any closed system with P, V work only, G is always minimized at equilibrium.
Statement(b) : G is always zero for a reversible process in a closed system.
Statemnent(c) : Gº for an ideal gas reaction is a function of pressure.
Statement(d) : For an irreversible, isothermal, isobaric process in a closed system with P, V work only G must
be negative.
(A) Statement a, b, d
(B) Statement b, c, d
(C) Statement c, d
(D) Only statement d
2.
Which of the following statement(s) is/are correct :
Statement(a) : The entropy of isolated system with P–V work only is always maximized at equilibrium.
Statement(b) : It is possible for the entropy of close system to decrease substantially in an irreversible process.
Statement(c) : Entropy can be created but not destroyed.
Statement(d) : SSystem is always zero for reversible process in an isolated system.
(A) Statement a, b, c
(B) Statement b, d
(C) Statement a, b, d
(D) All
3.
Which of the following statement(s) is/are incorrect:
Statement(a) : Reversible isothermal compression of an ideal gas represents the limiting minimum value of the
workdone (|w|) by the surrounding on the system.
Statement(b) : In an irreversible process, the cylic integral of work is not zero.
Statement(c) : For thermodynamic changes in adiabatic process.
 C p,m
 R
T


P cons tan t
Statement(d) : SSystem is zero for reversible adiabatic expansion of an ideal gas.
(A) Statement (c)
(B) Statement (a), (b), (c)
(C) Statement (a), (b), (d)
(D) All
4.
Pick out the incorrect statement among the following.
(I) Change in Gibb’s function at constant temperature and pressure in a process envolving no non–PV work is
equal to qrev – qirr.
(II) For a reaction with S0 is positive, as temperature is increased, Keq for the reaction increases necessarily.
(III) Exothermic reactions have lesser tendency to go in forward direction at higher temperature.
(IV) Decrease in Gibb’s function at constant temperature and pressure is equal to non PV work done by system
in spontaneous process.
(A) I, IV
(B) I, II, IV
(C) II, IV
(D) I, II
5.
Which of the following statement(s) is/are correct :
Statement(a) : If neither heat nor matter can enter or leave a system, that system must be isolated.
Statement(b) : q, w, E and H all are zero for adiabatic expansion of non ideal gas into vaccum.
Statement(c) : G is a state function.
Statement(d) : pH is an intensive property.
(A) Statement a, b, d
(B) Statement b, c, d
(C) Statement b, d
(D) Only b is correct
6.
Which of the following statement(s) is/are false ?
1
Cl (g)  Cl(g) is positive.
2 2
(B) E < 0 for combustion of CH4(g) in a sealed container with rigid adiabatic system.
(C) G is always zero for a reversible process in a closed system.
(D) Gº for an ideal gas reaction is a function of pressure.
(A) rS for
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7.
Statement–1 : Due to adiabatic free expansion, temperature of a real gas always increases.
Statement–2 : If a real gas is at inversion temperature then no change in temperature is observed in adiabatic
free expansion.
(A) Statement–1 is true, statement–2 is true; statement–2 is correct explanation for statement–1.
(B) Statement–1 is true, statement–2 is true; statement–2 is NOT correct explanation for statement–1.
(C) Statement–1 is true, statement–2 is false.
(D) Statement–1 is false, statement–2 is true.
8.
Select incorrect statement(s).
(A) Sº values for all elements at 298 K & 1 bar are positive.
(B) For the reaction 2H(g)  H2(g), H and S are positive.
(C) S System is negative for reversible adiabatic compression of an ideal gas.
(D) |w|adiabatic < |w|isothermal in compression process for an ideal gas.
9.


Statement–1 : When process H2O(s) 
 H2O(), reaches equilibrium in a closed system at constant
temperature and pressure, Gibb’s function of H2O(s) & H2O() become same.
Statement–2 : For reversible phase change at constant temperature & pressure, change in Gibb’s free energy will
be zero.
(A) Statement–1 is true, statement–2 is true; statement–2 is correct explanation for statement–1.
(B) Statement–1 is true, statement–2 is true; statement–2 is NOT correct explanation for statement–1.
(C) Statement–1 is true, statement–2 is false.
(D) Statement–1 is false, statement–2 is true.
10.
Pick out the incorrect statement among the following.
(A) Heat absorb during a change of state (P, V1, T1) to (P, V2, T2) in a closed system involving ideal gas must be
equal to H.
(B) Heat exchanged during a reversible isothermal process between two fixed states is a definite quantity.
(C) Complete conservion of heat into work is not possible in a reversible isothermal expansion of ideal gas.
(D) Complete conversion of heat into work is not possible in an irreversible isothermal expansion of ideal gas.
11.
For incomplete combustion of C(s) into CO(g)-pick out correct statement(s) from following:
C(s) +
1
 CO(g) :
O (g) 
2 2
H° is negative
(A) G° decreases as temperature is increased
(B) As temperature is increased, tendency of reaction to proceed in forward direction decreases
(C) At low temperature Stotal is less compared to it's value at higher temperature
(D) The equilibrium between reactant and product is not possible because G° is negative at all temperature,
12.


The enthalpy and entropy of trimerizatbo of gas A in gas phase [3A (g) 
 A3(g)] are –100 kJ/mol and –400
J/K mol respectively. The enthalpy of vapourisation for liquids A and A3 are respectively 25 kJ/raol and 50 kJ/rnol
respectively. If the boiling points of A and A3 are 300 K and 400 K respectively, then select correct statement(s):
(A) Enthalpy for trimerization of liquid is –75 kJ /mol
(B) Enthalpy for trimerization of liquid is –125 kJ /mol
(C) Entropy for trimerization of liquid is –775 J /K. mol
(D) G for trimerization of liquid is 7.5 kJ /mol
13.
Statement-1 : Under identical conditions, moist air diffuses faster than dry air.
Statement-2 : The rate of diffusion of gases increases with the decrease in molar mass of the gas and moist air
is lighter than dry air under identical condition.
(A) Statement-1( is true, statement-2 is true and statement-2 is correct explanation for statement-1.
(B) Statement-1 is true, statement-2 is true and statement-2 is NOT the correct explanation for statement-1
(C) Statement-1 is true, statement-2 is false
(D) Statement-1 is false, statement-2 is true
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14.
Select the correct option(s).
(A) Entropy change will be same for the adiabatic reversible and irreversible process if carried out from same
initial states tosame final volume
(B) A closed system having all adiabatic boundaries must be isolated system
(C) Work done in a cyclic process may be zero
(D) Area enclosed by a cyclic process on PV diagram is same as that of TS diagram.
15.
Which of the following is frue for reversible adiabatic process involving an ideal gas?
(A) Gas with higher  has high magnitude of slope in a P (y-axis) v/s T (x-axis) curve
(B) Gas with higher  has high magnitude of slope in a V (y-axis) v/s T (x-axis) curve
(C) Gas with higher  has high magnitude of slope in a P (y-axis) v/s V (x-axis) curve
(D) Gas with higher  has low magnitude of slope in a P (y-axis) v/s T (x-axis) curve
16.
Select the correct option.
(A) Adiabatic free expansion of a real gas having temperature less than inversion temperature results in decrease
in kinetic energy of gas
(B) More heat is absorbed by an ideal gas if subjected to reversible isothermal process than an irreversible
isothermal process between same states
(C) Final temperature of an ideal gas will be more for adiabatie reversible expansion process than isothermal
reversible expansion process if carried out from same initial state to same final pressure.
(D) On isothermal expansion of an ideal gas upto same final volume from same initial state, final pressure will
be more for irreversible process than reversible process.
17.
Statement-1: Absolute entropy of an ion in aqueous solution at 298 K may be negative.
Statement-2: Absolute entropy at 298 K of any substance can never be negative.
(A) Statement-1 is true, statement-2 is true and statement-2 is correct explanation for statement-1.
(B) Statement-1 is true, statement-2 is true and statement-2 is NOT the correct explanation for statement-1.
(C) Statement-1 is true, statement-2 is false.
(D) Statement-1 is false, statement-2 is true.
18.
Select the correct statements).
(A) dG = Vdp – SdT is applicable for all process involving both ‘TV’ and 'non-PV' work in a closed system
(B) Ssys can not be negative inany adiabatic process in a closed system
(C) U=0 for the combustion of C6H6(g) in a sealed rigid diathermic container
(D) In the presence of 'non-PV' work if (Gsys)T, P < 0, process must be spontaneous in a closed system.
19.
Which of the following statements is/are true?
(A) Reversible process and quasi static process are not same.
(B) At constant external pressure, the internal energy, U, of air (assuming it to be ideal) in a closed room is
dependent on temperature
(C) Arrow shown in the graph below, indicates decreasing value of .
P
V
(D)
In an adiabatic process, the internal energy increases at the expense of work done on the gas.
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20.
Which of the following is/are correct?
(A) Spherically symmetric complex of the type MX4 is generally, having low enthalpy than MX2 Y2
(B) More the value of ‘’ lesser will be the work done by gas in an adiabatic expansion process.
(C) Ideal gases produce more work in an isothermal reversible expansion as compared to Vanderwaal's gases,
assunring (V>>nb)
(D) Extensive properties are additive in nature but intensive are not.
21.
Select the incorrect statement(s):
(A) H f of CO2(g) is same as the H Combustion of carbon graphite.
(B)
The larger and more complex a molecule, the greater is it's absolute entropy.

H2(g) + Cl2(g) 
 2HCl(g) + 185 kJ. On the basis of above information H f (HCl, g) is 92.5 kj/mole.
(D) More volatile substance has high boiling point.
(C)
22.
Statement-1: There is no change in enthalpy of an ideal gas during compression at constant temperature
Statement -2 : Enthalpy of an ideal gas is a function of temperature and pressure.
(A) Statement-1 is true, statement-2 is true and statement-2 is correct explanation for statement- 1 .
(B) Statement-1 is true, statement-2 is true and statement-2 is NOT the correct explanation for statement- 1 .
(C) Statement-1 is false, statement-2 is true.
(D) Statement-1 is true, statement-2 is false.
23.
Which of the following statements) is/are false:
(A)
rS for
1
 N(g) is positive
N (g) 
2 2
(B) Gsystem is always zero for a reversible process in a closed system
(C) G° for an ideal gas is a function of temperature and pressure
(D) entropy ofa closed system is always maximized at equilibrium
24.
Select incorrect statement(s):
(A) Entropy of an isolated system always remains constant during phase transition process
(B) Ssurrounding < 0 for reversible condensation of vapour
(C) fG° > 0 for Br2(g) at high temperature.
(D) A2(g) + B2(g) 
 2AB(g) + 200 kJ.
On the basis of above information Hf°(AB, g) is 100 kJ/mole.
25.
Select correct statement(s):
(A) Work is an intensive property
(B) If enthalpy of solvation of ions A+(g) and B+(g) is greater than |Lattice energy|then Hsolution of AB(s) is
negative.
(C) In irreversible adiabatic compression of an ideal gas, increase in temperature is more as compare to
reversible adiabatic compression if process is carried out from same initial state to same final pressure.
(D) The equivalent weight of MnSO4 is half of it's molecular weight when it is converted to Mn2O3.
26.
Which statement is /are correct:
(A) Final temperature in reversible adiabatic expansion is lesser than in irreversible adiabatic expansion.
(B) When heat is supplied to an ideal gas in an isothermal process, kinetic energy of gas will increase
(C) When an ideal gas is subjected to adiabatic expansion it gets cooled
(D) Entropy increases in atomisation of dihydrogen.
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27.
Which is/are correct statement.
(A) wadiabatic> wisothetmal in anideal gas compression from same initial state to same final volume
(B)

The value of    

Cp 
remains constant for diatomic gas at all temperature
C 
v
(C) Entropy increases when an ideal gas expanded isothermally.
(D) rH & rS both are + ve for the decomposition of MgCO3(s).
28.
29.
In isothermal ideal gas compression:
(A) wis+ve
(B) H is zero
(C) Sgas is +ve
(D) G is+ve
Which of the following statements is /are correct?
(A) The loss of temperature by the hot body is always equal to the gain in temperature of the cold body, under
all conditions.
(B) Athermanous boundary does not allow heat to pass through them without becoming themselves hot
(C) Laws of thermodynamics can be applied to homogeneous system and to heterogeneous system which can
be divided into a number of homogeneous parts
(D) For a reversible process
 Wcyclic  0
30.
Select the correct options.
(A) The slope of constant volume line on the TS diagram is more than that of constant pressure line.
(B) In an isothermal process any amount of heat may be extracted ftom the system or any amount of heat
may be supplied without changing the temperature.
(C) An ideal monoatomic gas follows the process P5V7 = constant. If heat is withdrawn from the system then
temperature always increases
(D) A reversible engine operates between two temperature THot and TCold in summers. If same engine is used in
winters then amount of Rxergy decreases.
31.
Select the correct option(s).
(A) A cycle is drawn on PV diagram in which there is one isothermal expansion & two adiabats (expansion &
compression), then engine is 100% efficiency.
(B) A cycle is drawn on PV diagram in which there is one isothermal expansion & two adiabats (expansion &
compression ), then engine is not possible.
(C) Carnot engine has same efficiency if ideal gas or real gas is taken as fluid.
(D) First law of thermodynamic for open system is dependent on mass exchange and enthalpy.
32.
Which of the following statement(s) is/are correct?
(A) The quantities E, H and G have the same dimension
(B) Gibb's free energy of 10 gm ice at 0°C and 1.0 atm is less than the Gibb's free energy of 10 gm water at 0°C
and 1 atm.
(C) Ssys = 0 for every adiabatic process ina closed system.
(D)
33.
For every reversible process, in a closed system, Ssys=
H sys
T
Select the correct option(s):
(A) U = 0 for a chemical change occuring at constant temperature.
(B) For an ideal gas undergoing a process for which AU = 0, then H must be zero.
(C) For an ideal gas undergoing any process W=-nRT
(D) For an adiabatic irreversible process involving an ideal gas dH = nCP dT
m
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34.
Statement-1: For adiabatic free expansion of a real gas H = 0.
Statement-2: In adiabatic free expansion W = 0, Q = 0, U = 0 for ideal as well as real gas.
(A) Statement- 1 is true, statement-2 is true and statement-2 is correct explanation for statement-1
(B) Statement-1 is true, statement-2 is true and statement-2 is NOT the correct explanation for statement-1
(C) Statement-1 is true, statement-2 is false.
(D) Statement-1 is false, statement-2 is true.
35.
Select the correct statement(s),
(A) In a reversible process G is always zero in a closed system.
(B) In a reversible process Suniv is always zero in a closed system.
(C) In a reversible process Ssys is always zero in a closed system.
(D) In a reversible process Ssys is always zero in an isolated system.
36.
Select the correct option(s):
(A) q = nCvdT is applicable to all substances during heating / cooling at constant ‘v’
(B) q = nCvdT is applicable to ideal gas during heating / cooling at constant ‘v’ only
(C) dU = nCvdT is applicable for real gas at constant V
(D) dU = nCvdT is applicable for ideal gas at constant V only.
37.
For an adiabatic irreversible process involving an ideal gas
(A) U = nCvT
(B) w = nCvT
(C) w = –Pext (V2 – V1)
(D) U = –Pext (V2 – V1)
38.
A(g)  2B(g) ; H = 1 0 kJ/mole at 300 K
CP, A = 20 J/Kmol and CP, B = 20 J/Kmol.
If we assume ideal behaviour of gases. Which of the following statement are incorrect?
(A) H will be increase on increasing temperature at constant pressure
(B) H will decrease on increasing temperature at constant pressure.
(C) H will decrease on increasing pressure at constant temperature.
(D) H will increase on increasing pressure at constant temperature.
39.
For the process : H2O (l,TK, P bar)  H2O (g, TK, P; bar)
(A) G = 0, if P = vapour pressure of H2O(l) at TK
(B) G = +ve, if P = vapour pressure of H2O (l) at a temperature above TK
(C) G =+ve ; if P > vapour pressure of H2O (l) at TK
(D) G = –ve ; if P < vapour pressure of H2O (l) at TK
40.
In the P & V diagram shown for an ideal gas undergoing ABCDA process. Choose the correct option(s)
P
A
D
B
Pvx = const & x=1
V
(A) The area enclosed by ABCDA curve gives the net work done on the system,
(B) Area under the curve CDA gives the work involved in CDA process.
(C) In process CDA first the temperature of the process increases and then decreases.
(D) The temperatures at point A, B & C is same.
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41.
Select the incorrect statement(s).
(A) dG = Vdp - SdT is applicable for all process involving both ‘PV’ and ‘non-PV’ work in a closed system.
(B) Ssys can not be negative in any adiabatic process in a closed system.
(C) U=0 for the combustion of C6H6 (g) in asealed rigid diathermic container.
(D) In the presence of 'non-PV' work if (Gsay)T, P < 0, process must be spontaneous in a closed system.
42.
Super cooled rain water (–1°C) strikes the wind screen of a car and converts to ice in winter season.
With reference to second law of thermodynamics which statement is correct for above process.
(A) Randomness of universe decreases as ice possess less disorder than liquid water.
(B) Randomness of surrounding decreases
(C) Water to ice conversion is equilibrium process thus increase in randomness is surrounding is equal to
decrease in randomness of system.
(D) Increase in randomness of surrounding is greater than decrease in randomness of system.
43.
Which of trie following statements) is/are correct?
(A) The internal energy of an ideal gas may be increased by adding more molecules to it, at constant
temperature.
(B) The moiar enthalpy of any substance decreases on cooling, at constant pressure.
(C) Adiabatic free expansion & isothermal free expansion are similar processes for an ideal gas.
(D) It is not possible to have a process in which the entropy of an isolated system is decreased.
44.
Which of the following process must be spontaneoas?
(A) A process at constant pressure and constant entropy in which H is negative.
(B) An adiabatic process in which S is positive and volume remains constant.
(C) An isobaric process in which U is negative and entropy remains constant.
(D) A process occurring at constant pressure and temperature in which G is negative.
45.
Sratement-1: For a definite amount of an ideal gas, the internal energy of gas increases in isothermal expansion.
Statement-2 : There areno intermolecular forces among the molecules of an ideal gas.
(A) Statement-1 is true, statement-2 is true and statement-2 is correct explanation for statement-1.
(B) Statement-1 is hue, statement-2 i s true and statement-2 is NOT the correct explanation for statement-1.
(C) Statement-1 is true, statement-2 is false.
(D) Statement-1 is false, statement-2 is true.
46.
Statement-1: For an irreversible cyclic process in a closed system Ssurr= 0.
Statement-2: Entropy is a state function.
(A) Statement-1 is true, statement-2 is true and statement-2 is correct explanation for statement-1.
(B) Statement-1 is true, statement-2 is true and statement-2 is NOT the correct explanation for statement-1.
(C) Statement-1 is hue, statement-2 is false
(D) Statement-1 is false, statement-2 is true
47.
Which of the following statements is incorrect?
(A)
Hvap H 2O(l) > 21 × 373 Cal
(B)
 T  0 for all cyclic processes.
q
(C) Adiabatic reversible process is isoentropic
(D) Heat exchange at constant volume condition will be independent of path.
*****
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THERMODYNAMICS
ONE OR MORE THAN ONE CORRECT TYPE
1.
(D)
2.
(D)
3.
(A)
4.
(B)
5.
6.
(BCD)
7.
(D)
8.
(BCD)
9.
(D)
10. (ACD)
11.
(ACD)
12.
(AD)
13.
(A)
14.
(CD)
15.
(CD)
16.
(AB)
17.
(C)
18.
(B)
19.
(A)
20.
(ABCD)
21.
(CD)
22.
(D)
23.
(BCD)
24.
(ABCD)
25.
(BC)
26.
(ACD)
27.
(ACD)
28.
(ABD)
29.
(BCD)
30.
(ABC)
31.
(BCD)
32.
(A)
33.
(BD)
34.
(D)
35.
(BD)
36.
(ABC)
37.
(ABCD)
38.
(BCD)
39.
(ABCD)
40.
(ABD)
41.
(ACD)
42.
(D)
43.
(ABCD)
44.
(ABD)
45.
(D)
46.
(D)
47.
(B)
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(C)