In the reaction, both H and S are positive. The condition(s) under which the reaction would not be spontaneous are/is:

1. H>TS                             

2. S=H/T

3. H=TS                               

4. All of the above

Subtopic:  Gibbs Energy Change |
 55%
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The entropy change in the fusion of one mole of a solid melting at 27°C  is:       

(the latent heat of fusion is 2930 J mol-1)                                                                                   

1. 9.77 JK-1mol-1               

2. 19.73 JK-1mol-1               

3. 2930 JK-1mol-1               

4. 108.5 JK-1mol-1          

Subtopic:  Spontaneity & Entropy |
 80%
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1 mole of an ideal gas at 25°C is subjected to expand reversibly ten times of its initial volume.
The change in entropy of expansion is:

1. 19.15 JK–1mol–1                         

2. 16.15 JK–1mol–1

3. 22.15 JK–1mol–1                         

4. None of the above

Subtopic:  Spontaneity & Entropy |
 67%
From NCERT
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Determine the enthalpy change for the specified reaction:

2H2O2(l 2H2O(l) + O2(g).

(Given the heat of formation of H2O2(l) and H2O(l) are –188 and –286 kJ/mol respectively)       

1. –196 kJ/mol 2. +196 kJ/mol
3. +948 kJ/mol 4. –948 kJ/mol
Subtopic:  Enthalpy & Internal energy |
 69%
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Entropy decreases in which of the following reactions?

1. Boiling of egg

2. Combustion of benzene at 127°C

3. Stretching of rubber band

4. Dissolution of sugar in water

Subtopic:  Spontaneity & Entropy |
 61%
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Equilibrium is represented by:

1. H = 0             

2. GTotal = 0

3. STotal = 0         

4. E = 0

Subtopic:  Gibbs Energy Change |
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For exothermic reaction to be spontaneous (S=negative) temperature must be -

1. High 2. Zero
3. Constant 4. Low
Subtopic:  Spontaneity & Entropy |
 67%
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'The free energy change due to a reaction is zero when-

1. The reactants are initially mixed.

2.  A catalyst is added

3. The system is at equilibrium

4. The reactants are completely consumed

Subtopic:  Gibbs Energy Change |
 88%
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For a given reaction, if ΔH = 35.5 kJ/mol and ΔS = 83.6 J/K·mol, at what temperature is the reaction spontaneous?
(Assume ΔH and ΔS remain constant with temperature.)

1. T < 425 K 2. T > 425 K
3. All temperatures 4. T > 298 K
Subtopic:  Gibbs Energy Change |
 74%
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NEET - 2017
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The standard enthalpy of vaporisation vapH° for water at 100°C is 40.66 kJ mol-1. The

internal energy of vaporisation of water at 100°C (in kJ mol-1) is- 

(Assume water vapour to behave like an ideal gas)

1. +37.56                   

2. -43.76

3. +43.76                   

4. +40.66

Subtopic:  Enthalpy & Internal energy |
 59%
From NCERT
NEET - 2012
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