For an endothermic reaction:
A. \(q_p \) (heat at constant pressure) is negative.
B. \(\Delta _r H \) (enthalpy change of the reaction) is positive.
C. \(\Delta _r H \) is negative. 
D. \(q_p \) is positive.
Which of the following combinations is correct?
1. B and D  2. C and D 
3. A and B  4. A and C
Subtopic:  Thermodynamics' Properties and process |
 73%
Level 2: 60%+
NEET - 2024
Hints

Match List I with List II.
List-I (Process) List-II (Conditions)
A. Isothermal process I. No heat exchange
B. Isochoric process II. Carried out at constant temperature
C. Isobaric process III. Carried out at constant volume
D. Adiabatic process IV. Carried out at constant pressure
Choose the correct answer from the options given below:
1. \(\text { A-IV, B-II, C-III, D-I }\) 2. \(\text { A-I, B-II, C-III, D-IV }\)
3. \(\text { A-II, B-III, C-IV, D-I }\) 4. \(\text { A-IV, B-III, C-II, D-I }\)
Subtopic:  Thermodynamics' Properties and process |
 86%
Level 1: 80%+
NEET - 2024
Hints

Match the processes or properties in List-I with their corresponding characteristics in List-II.
List-I
(Process/Property)
List-II
(Characteristic)
A. Adiabatic process I. Independent of the amount of substance 
B. Reversible process II. The reaction can proceed in both directions, from reactants to products and vice versa
C. Intensive property III. No transfer of heat between the system and the surrounding
D. Extensive property IV. Dependent on the amount of substance 
Choose the correct answer from the options given below:
1. A-II, B-III, C-IV, D-I 2. A-I, B-II, C-IV, D-III
3. A-III, B-II, C-I, D-IV 4. A-I, B-II, C-III, D-IV
Subtopic:  Classification of System, Extensive & Intensive Properties |
 93%
Level 1: 80%+
NEET - 2024
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Consider the following reaction:
\(\mathrm{A}_2(\mathrm{~g})+3 \mathrm{~B}_2(\mathrm{~g}) \rightarrow 2 \mathrm{AB}_3(\mathrm{~g})\)
If at 300K, the enthalpy change for the above reaction is +15 kJ, then the internal energy change is:
1. 19.98 K J  2. 200 J
3. 1999 J  4. 1.9988 kJ
Subtopic:  Enthalpy & Internal energy |
 77%
Level 2: 60%+
NEET - 2024
Hints

For the reaction, 2Cl(g)  Cl2(g), the correct option is:
1. \(\Delta_{\mathrm{r}} \mathrm{H}>0\) and \(\Delta_{\mathrm{r}} \mathrm{S}<0 \) 2. \(\Delta_{\mathrm{r}} \mathrm{H}<0\) and \( \Delta_{\mathrm{r}} \mathrm{S}>0 \)
3. \(\Delta_{\mathrm{r}} \mathrm{H}<0 \) and \(\Delta_{\mathrm{r}} \mathrm{S}<0 \) 4. \(\Delta_{\mathrm{r}} \mathrm{H}>0\) and \( \Delta_{\mathrm{r}} \mathrm{S}>0\)
Subtopic:  Enthalpy & Internal energy | Spontaneity & Entropy |
 61%
Level 2: 60%+
NEET - 2020
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The standard enthalpy of vaporization vapHo for water at 100 oC is 40.66 kJ mol–1. The internal energy of vaporization of water at 100 oC (in kJ mol–1) is: 
(Assume water vapour behaves like an ideal gas.)

1. +37.56 2. –43.76
3. +43.76 4. +40.66
Subtopic:  Enthalpy & Internal energy |
 61%
Level 2: 60%+
AIPMT - 2012
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Work done during reversible isothermal expansion of one mole of hydrogen gas at 25°C from a pressure of 20 atmospheres to a pressure of 10 atmospheres is:
(Given: R = 2.0 cal K–1 mol–1)
1. –413.14 calories 2. 413.14 calories 
3. 100 calories 4. 0 calorie
Subtopic:  First Law of Thermodynamics |
 72%
Level 2: 60%+
NEET - 2024
Hints

Determine \(\Delta U\) for the process where, one mole of an ideal gas at 300 K is expanded isothermally from 1 L to 10 L volume:
(Use R = 8.314 J K–1 mol–1)
1. 1260 J 2. 2520 J
3. 5040 J 4. 0 J
Subtopic:  First Law of Thermodynamics |
 80%
Level 1: 80%+
NEET - 2022
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
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A gas is allowed to expand in a well-insulated container against a constant external pressure of 2.5atm from an initial volume of 2.50 L to a final volume of 4.50L. The change in internal energy U of the gas in joules will be:

1. –500J 2. –505J
3. –506J 4. –508J
Subtopic:  First Law of Thermodynamics |
Level 3: 35%-60%
NEET - 2017
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