The entropy values (in JK-1 mol-1) of H2(g) = 130.6, Cl2(g) = 223.0 and HCl(g) = 186.7 at 298 K and 1 atm pressure. Then entropy change for the reaction H2(g)+Cl2(g)2HCl(g) is

(1) + 540.3

(2) + 727.3

(3) – 166.9

(4) + 19.8

Subtopic:  Spontaneity & Entropy |
 77%
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NEET 2023 - Target Batch - Aryan Raj Singh
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The ΔS for the vaporization of 1 mol of water is 88.3 J/mole K. The value of ΔS for the condensation of 1 mol of vapour will be

       1. 88.3 J/mol K

2. (88.3)2 J/mol K

3. – 88.3 J/mol K

4. 188.3 J/mol K        

Subtopic:  Spontaneity & Entropy |
 78%
From NCERT
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NEET 2023 - Target Batch - Aryan Raj Singh
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NEET 2023 - Target Batch - Aryan Raj Singh

The occurrence of a reaction is impossible if -

1. ΔH is +ve ; ΔS is also + ve but ΔH < TΔS

2. ΔH is – ve ; ΔS is also – ve but ΔH > TΔS

3. ΔH is – ve ; ΔS is + ve

4. ΔH is + ve ; ΔS is – ve

Subtopic:  Spontaneity & Entropy |
 69%
From NCERT
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NEET 2023 - Target Batch - Aryan Raj Singh
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NEET 2023 - Target Batch - Aryan Raj Singh

The enthalpy and entropy change for a chemical reaction are

–2.5 × 103 cal and 7.4 cal deg–1 respectively.  Predict the reaction at 298 K is

1. Spontaneous

2. Reversible

3. Irreversible

4. Non-spontaneous

Subtopic:  Gibbs Energy Change |
 84%
From NCERT
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NEET 2023 - Target Batch - Aryan Raj Singh
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NEET 2023 - Target Batch - Aryan Raj Singh

Which of the following is true for the reaction H2O(l)H2O(g) at 100°C and 1 atmosphere

1. ΔE = 0

2. ΔH = 0

3. ΔH = ΔE

4. ΔH = TΔS

Subtopic:  Gibbs Energy Change |
 68%
From NCERT
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NEET 2023 - Target Batch - Aryan Raj Singh
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The enthalpy of vapourization water is 386 kJ. What is the entropy of water

(1) 0.5 kJ

(2) 1.03 kJ

(3) 1.5 kJ

(4) 22.05 kJ

Subtopic:  Spontaneity & Entropy |
 78%
From NCERT
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NEET 2023 - Target Batch - Aryan Raj Singh
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Identify the correct statement regarding entropy [CBSE PMT 1998; BHU 2001]

1. At 0°C, the entropy of a perfectly crystalline substance is taken to be zero

2. At absolute zero temperature, the entropy of a perfectly crystalline substance is +ve

3. At absolute zero temperature, the entropy of all crystalline substances is taken to be zero

4. At absolute zero temperature, the entropy of a perfectly crystalline substance is taken to be zero

Subtopic:  Spontaneity & Entropy |
 62%
From NCERT
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NEET 2023 - Target Batch - Aryan Raj Singh
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NEET 2023 - Target Batch - Aryan Raj Singh

An engine operating between 150°C and 25°C takes 500 J heat from a higher temperature reservoir if there are no frictional losses, then work done by engine is [MH CET 1999]

(1) 147.7 J

(2) 157.75 J

(3) 165.85 J

(4) 169.95 J

Subtopic:  First Law of Thermodynamics |
 53%
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The standard entropies of CO2(g), C(s) and O2(g) are 213.5, 5.690 and 205 JK–1 respectively. The standard entropy of formation of CO2(g) is

(1) 1.86 JK–1

(2) 1.96 JK–1

(3) 2.81 JK–1

(4) 2.86 JK–1

Subtopic:  Thermochemistry |
 76%
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NEET 2023 - Target Batch - Aryan Raj Singh
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Equal volumes of monoatomic and diatomic gases at same initial temperature and pressure are mixed. The ratio of specific heats of the mixture (Cp/Cv) will be [AFMC 2002]

(1) 1

(2) 2

(3) 1.67

(4) 1.5

Subtopic:  Cp & Cv |
 51%
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