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 |
 61%
From NCERT
AIPMT - 2007
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The enthalpy and entropy change for the reaction: Br2 (l) + Cl2 (g) →2BrCl(g), are 30kJ mol-1 and 105 JK-1 mol-1 respectively. The temperature at which the reaction will be in equilibrium is: 

1. 285.7 K

2. 273 K

3. 450 K

4. 300 K

Subtopic:  Gibbs Energy Change |
 72%
From NCERT
AIPMT - 2006
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The enthalpy of combustion of H2, cyclohexene (C6H10) and cyclohexane (C6H12) are -241, -3800 and -3920 kJ per mol respectively. Heat of hydrogenation of cyclohexene is:

1. -121 kJ per mol

2. +121 kJ per mol

3. +242 kJ per mol

4. -242 kJ per mol

Subtopic:  Thermochemistry |
 56%
From NCERT
AIPMT - 2006
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Under the isothermal condition, a gas at 300 K expands from 0.1 L to 0.25 L against a constant external pressure of 2 bar. The work done by the gas is:
[Given that 1 L bar = 100 J]

1. 30 J

2. –30 J

3. 5 kJ

4. 25 J

Subtopic:  2nd & 3rd Law of Thermodynamics |
 79%
From NCERT
NEET - 2019
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A process among the following shows decrease in entropy is :

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 solid to gas

Subtopic:  Gibbs Energy Change |
 80%
From NCERT
NEET - 2019
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Consider the following reactions: 

(i) H+(aq) + OH-(aq) → H2O(l)
ΔH = -x1 kJmol-1
(ii) H2(g) + 1/2O2(g) → H2O(l)
ΔH = -x2 kJmol-1
(iii) CO2(g) + H2(g) → CO (g) + H2O(l)
ΔH = -x3 kJmol-1
(iv) C2H2(g) + 5/2O2(g) →  2CO+ H2O(l)
ΔH = -x4 kJmol-1


Enthalpy of formation of H2O(l) is :

1. -x3 kJ mol-1

2. -x4 kJ mol-1

3. -x1 kJ mol-1

4. -x2 kJ mol-1

Subtopic:  Thermochemistry |
 75%
From NCERT
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 |
 64%
From NCERT
AIPMT - 2008
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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 |
 81%
From NCERT
AIPMT - 2008
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Which of the following are not state functions? 
(I) q + W 
(II) q 
(III) W 
(IV) H - TS

1. (I) and (IV)
2. (II), (III) and (IV)
3. (I), (II) and (III)
4. (II) and (III)
Subtopic:  Gibbs Energy Change |
 76%
From NCERT
AIPMT - 2008
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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%
From NCERT
AIPMT - 2009
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