Which of the following statements is correct for the spontaneous adsorption of a gas?

1. ∆ S is negative and therefore,  ∆ H should be highly positive
2. ∆ S is negative and therefore,  ∆ H should be highly negative
3. ∆ S is positive and therefore,  ∆ H should be negative
4. -∆ S is positive and therefore,  ∆ H should also be highly positive

Subtopic:  Spontaneity & Entropy |
 57%
From NCERT
AIPMT - 2014
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NEET 2023 - Target Batch - Aryan Raj Singh
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NEET 2023 - Target Batch - Aryan Raj Singh

Given the following reaction:
\(4H(g)\)→  \(2 H_{2}\)\((g)\)
The enthalpy change for the reaction is -869.6 kJ. The dissociation energy of the H-H bond is:
1. -869.6 kJ
2. +434.8kJ
3. +217.4kJ
4. -434.8 kJ

Subtopic:  Enthalpy & Internal energy |
 68%
From NCERT
AIPMT - 2011
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NEET 2023 - Target Batch - Aryan Raj Singh
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From the following bond energies:
H—H bond energy: 431.37 kJ mol-1 
C=C bond energy: 606.10 kJ mol-1 
C—C bond energy: 336.49 kJ mol-1 
C—H bond energy: 410.50 kJ mol-1 
Enthalpy for the reaction, 

will be:

1. 1523.6 kJ mol-1 2. -243.6 kJ mol-1
3. -120.0 kJ mol-1 4. 553.0 kJ mol-1
Subtopic:  Thermochemistry |
 75%
From NCERT
AIPMT - 2009
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NEET 2023 - Target Batch - Aryan Raj Singh
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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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NEET 2023 - Target Batch - Aryan Raj Singh
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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 |
 54%
From NCERT
AIPMT - 2008
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NEET 2023 - Target Batch - Aryan Raj Singh
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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 |
 60%
From NCERT
AIPMT - 2007
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NEET 2023 - Target Batch - Aryan Raj Singh
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Two moles of an ideal gas is heated at a constant pressure of one atmosphere from 27°C to 127°C. If Cv, m=20+10-2 T JK-1 mol-1,  then q and U for the process are respectively:

1.  6362.8 J, 4700 J

2.  3037.2 J, 4700 J

3.  7062.8 J, 5400 J

4.  3181.4 J, 2350 J

Subtopic:  Cp & Cv |
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Calculate fH° (in kJ/mol) for Cr2O3 from the rG° and the S° values provided at 27°C

4Crs+3O2g  2Cr2O3s; 
rG°=-2093.4 kJ/mol

S°J/K mol : S°Cr, s=24; 
S°O2, g=205;   S°Cr2O3, s=81

1.  -2258.1 kJ/mol

2.  -1129.05 kJ/mol

3.  -964.35 kJ/mol

4.  None of the above

Subtopic:  Gibbs Energy Change |
From NCERT
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Given the Gibbs free energy change, \(\Delta G^\circ=+63.3~kJ,\) for the following reaction, 
\(Ag_2 CO_3 (g) \rightarrow 2Ag^+ (aq) + CO^{2-}_3 (aq)\)
\(K_{sp}\) of \(Ag_2CO_3 (s) \) in water at 25º C is (R = 8.314 JK-1 mol-1)

1. \(3.2 \times 10^{26}\)
2. \(8.0 \times 10^{-12}\)
3. \(2.9 \times 10^{-3}\)
4. \(7.9 \times 10^{-2}\)
Subtopic:  Gibbs Energy Change |
 60%
From NCERT
AIPMT - 2014
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NEET 2023 - Target Batch - Aryan Raj Singh
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The correct statement for a reversible process in a state of equilibrium is:
1. G = - 2.30RT log K
2. G = 2.30RT log K
3. Go = - 2.30RT log K
4. Go = 2.30RT log K

Subtopic:  Gibbs Energy Change |
 78%
From NCERT
NEET - 2015
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NEET 2023 - Target Batch - Aryan Raj Singh
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