Reversible expansion of an ideal gas under isothermal and adiabatic conditions are shown in the figure:

AB→Isothermal expansion

AC→Adiabatic expansion

Which of the following options is not correct?

1. \(\Delta S_{\text {isothermal }}>\Delta S_{\text {adiabatic }} \) 2. \(T_A=T_B \)
3. \(W_{\text {isothermal }}>W_{\text {adiabatic }} \) 4. \(T_C>T_A\)

Subtopic:  2nd & 3rd Law of Thermodynamics |
 55%
Level 3: 35%-60%
NEET - 2019
Hints

What is the amount of work done by an ideal gas, if the gas expands isothermally from \(10^{-3}~m^3\) to \(10^{-2}~m^3\) at \(300~K\)against a constant pressure of \(10^{5}~Nm^{-2}\)?

1. \(+270 ~kJ\) 2. \(–900 ~J\)
3. \(+900 ~kJ\) 4. \(–900~ kJ\)
Subtopic:  First Law of Thermodynamics |
 72%
Level 2: 60%+
NEET - 2019
Hints

Which of the following processes shows a decrease in entropy?

1. \(2 \text H \left(g\right)\rightarrow\text H_{2} \left(g\right)\)

2. Evaporation of water

3. Expansion of a gas at a constant temperature

4. Sublimation of a solid to a gas

Subtopic:  Gibbs Energy Change |
 82%
Level 1: 80%+
NEET - 2019
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Under the isothermal condition, a gas at \(300 \mathrm{~K}\) expands from \(0.1 \mathrm{~L}\) to \(0.25 \mathrm{~L}\) against a constant external pressure of 2 bar. The work done by the gas is:

1. \(30 ~\mathrm {J} \) 2. \(-30 ~\mathrm{J} \)
3. \(5~ \mathrm{kJ}\) 4. \(25~ \mathrm{J}\)
Subtopic:  2nd & 3rd Law of Thermodynamics |
 81%
Level 1: 80%+
NEET - 2019
Hints

Assuming each reaction is carried out in an open container,
Reaction that shows ΔH=ΔE is :

1. H2(g)+Br2(g)→2HBr(g)

2. C(s)+2H2O(g)→2H2(g)+CO2(g)

3. PCl5(g)→PCl3(g)+Cl2(g)

4. 2COg+O2g→2CO2g

Subtopic:  Thermodynamics' Properties and process |
 82%
Level 1: 80%+
AIPMT - 2006
Hints

The bond energy of H—H and Cl-Cl is 430 kJ
mol-1 and 240 kJ mol-1 respectively and ΔHf for HCl is -90 kJ mol-1. The bond enthalpy of HCl is:

1. 290 kJ mol-1

2. 380 kJ mol-1

3. 425 kJ mol-1

4. 245 kJ mol-1

Subtopic:  Thermochemistry |
 63%
Level 2: 60%+
AIPMT - 2007
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Bond dissociation enthalpy of H2, Cl2, and HCl are 434, 242, and 431 kJ mol1 respectively. Enthalpy of formation of HCl is:
1. 93 kJ mol-1
2. - 245 kJ mol-1
3. -93 kJ mol-1
4. 245 kJ mol-1
Subtopic:  Thermochemistry |
 66%
Level 2: 60%+
AIPMT - 2008
Hints

The standard free energies of formation(in kJ/mol) at 298 K are -237.2, -394.4, and -8.2 for H2O(l), CO2(g), and pentane (g), respectively. The value of Ecell for the pentane-oxygen fuel cell is:

1. 1.968 V
2. 2.0968 V
3. 1.0968 V
4. 0.0968 V

Subtopic:  Gibbs Energy Change |
 52%
Level 3: 35%-60%
AIPMT - 2008
Hints

For the gas phase reaction, 
 PCl5(g)⇌PCl3(g)+Cl2(g)
which of the following conditions is correct?

1. ΔH = 0 and ΔS < 0

2. ΔH > 0 and ΔS > 0

3. ΔH < 0 and ΔS < 0

4. ΔH > 0 and ΔS < 0

Subtopic:  Gibbs Energy Change |
 83%
Level 1: 80%+
AIPMT - 2008
Hints

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The values of ΔH and ΔS for the given reaction are 170 kJ and 170 JK-1, respectively.
C(graphite) + CO2(g)→2CO(g) 
This reaction will be spontaneous at:

1. 710 K
2. 910 K
3. 1110 K
4. 510 K

Subtopic:  Gibbs Energy Change |
 88%
Level 1: 80%+
AIPMT - 2009
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