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Thermodynamics (C) — NEET UG Chemistry PYQs

730 previous year questions from Thermodynamics (C) with answers and solutions. Numbered list, year tags, and one-tap solutions — built for serious JEE / NEET practice.

730 questionsChemistrySolutions on every page
1

A certain organic solvent has H _vap = 28.50 kJ mol ⁻¹ and S _vap = 88.2 J K ⁻¹ mol ⁻¹ at 1 bar. Calculate its normal boiling point (where G = 0 ).

MHT CET Medical 2026 Solution View → 2

Which of the following statements regarding spontaneous process is NOT true?

MHT CET Medical 2026 Solution View → 3

Calculate H for a reaction, 2X_ (g) + Y_ (g) 2Z_ (g) at 298 K if U = -10.5 kJ and R = 8.314 J K ⁻¹ mol ⁻¹ .

MHT CET Medical 2026 Solution View → 4

500 mL of nitrogen gas and 750 mL hydrogen gas were allowed to react at 1 bar pressure according to reaction, N _ 2(g) + 3 H _ 2(g) 2 NH _ 3(g) What is PV type of work done during

MHT CET Medical 2026 Solution View → 5

The relationship between H and U for the reaction, PCl ₃(g) + Cl ₂(g) PCl ₅(g) is given as

MHT CET Medical 2026 Solution View → 6

What would be the heat released in kJ when 450 cm ^3 of 0.02 M H ₂ SO ₄ is mixed with 650 cm ^3 of 0.1 M NaOH ? (Heat of neutralization of H ₂ SO ₄ and NaOH is -114 kJ/mol of H ₂ S

MHT CET Medical 2026 Solution View → 7

Identify from following reactions that it takes place with H = U .

MHT CET Medical 2026 Solution View → 8

Calculate the work done in the following reaction at 300 K , A (g) + B (g) = 2 C (g) [R = 8.314 JK ⁻¹ mol ⁻¹]

MHT CET Medical 2026 Solution View → 9

The bond enthalpies of H-H, Cl-Cl, and H-Cl bonds are 437 kJ/mol, 239 kJ/mol, and 433 kJ/mol respectively. Calculate the enthalpy of formation of HCl.

MHT CET Medical 2026 Solution View → 10

Which of the following is applicable for isothermal process?

MHT CET Medical 2026 Solution View → 11

What is the work done in the formation of 1 mole gaseous methane from solid carbon and gaseous hydrogen at 27^ C ? ( R=8.314 J k ⁻¹ mol ⁻¹ )

MHT CET Medical 2026 Solution View → 12

Which of the following physical transformations is an exothermic?

MHT CET Medical 2026 Solution View → 13

1 mole of certain gas expands isothermally and reversibly from 1 dm ^3 to 10 dm ^3 and performs -4308 J work. Calculate the temperature at which expansion of gas takes place [R = 8

MHT CET Medical 2026 Solution View → 14

Which of the following processes is an example of decrease in entropy?

MHT CET Medical 2026 Solution View → 15

Calculate the enthalpy of formation of HCl if bond enthalpies of H - H , Cl - Cl and H - Cl bonds are 434 kJ mol ⁻¹ , 242 kJ mol ⁻¹ and 431 kJ mol ⁻¹ , respectively.

MHT CET Medical 2026 Solution View → 16

When is the reaction spontaneous?

MHT CET Medical 2026 Solution View → 17

Determine the constant external pressure required to compress 2 mole of an ideal gas from volume 10.8 dm ^3 to 5.4 dm ^3 if the work obtained is 2460 J.

MHT CET Medical 2026 Solution View → 18

For a certain reaction, the enthalpy change and entropy change are +50 kJ and -50 J/K respectively at 27^ C, What is the Gibbs free energy change of reaction?

MHT CET Medical 2026 Solution View → 19

What is the enthalpy of formation of HF if bond enthalpies of H-H, F-F and H-F bonds are 434 kJ/mol, 158 kJ/mol and 565 kJ/mol respectively. ?

MHT CET Medical 2026 Solution View → 20

Which of the following properties of the system is both state function and intensive property as well?

MHT CET Medical 2026 Solution View → 21

Which of the following is NOT an intensive property?

MHT CET Medical 2026 Solution View → 22

If, i) C + 2 S CS ₂ , H = 117 kJ ii) C + O ₂ CO ₂ , H = -393 kJ iii) S + O ₂ SO ₂ , H = -297 kJ Find the heat of combustion of CS ₂ .

MHT CET Medical 2026 Solution View → 23

Calculate the amount of work done in the oxidation of 1 mole of HCl(g) at 127^ C if 4 , HCl(g) + O ₂ (g) 2 Cl ₂ (g) + 2 H ₂ O(g) ; [ R = 8.314 JK ⁻¹ mol ⁻¹ ]

MHT CET Medical 2026 Solution View → 24

A gas is compressed by an average pressure of 0.50 atmosphere, so as to decrease its volume from 400 cm ^3 to 200 cm ^3 . What will be the work done in this case?

MHT CET Medical 2026 Solution View → 25

In which of the following changes, entropy of the system decreases?

MHT CET Medical 2026 Solution View → 26

Enthalpy of combustion of carbon to carbon dioxide is -390 kJ/mol . What is the amount of heat released when 35 g of carbon dioxide is formed from the reaction of carbon and dioxyg

MHT CET Medical 2026 Solution View → 27

The ' x ' moles gas is allowed to expand isothermally and reversibly from 10 dm ^3 to 20 dm ^3 at 300 K and -17290 J work is obtained. Find the value of ' x '. [2.303 R = 19.15 J K

MHT CET Medical 2026 Solution View → 28

Which of the following processes exhibits that U = Q_v ?

MHT CET Medical 2026 Solution View → 29

Standard enthalpy of vaporization _ vap H^0 for water at 100^ C is 40.66 kJ mol ⁻¹ . What is the internal energy of vaporization of water at 100^ C (in kJ mol ⁻¹ )?

MHT CET Medical 2026 Solution View → 30

Determine the temperature at which 2 moles of oxygen gas expands isothermally and reversibly from 2 dm ^3 to 20 dm ^3 performs -11490 J of work [2.303 R = 19.15 JK ⁻¹ mol ⁻¹]

MHT CET Medical 2026 Solution View → 31

Calculate the work done when an ideal gas expands from 1 10⁻³ to 1 10⁻² m ^3 at 300 K against constant pressure of 1 10^5 Nm ⁻² . ?

MHT CET Medical 2026 Solution View → 32

What is the work done when an ideal gas (0.300 mol) expands in vacuum?

MHT CET Medical 2026 Solution View → 33

For a reaction, G ^ = -5.7 kJ mol ⁻¹ at 298 K. Calculate K. ( R = 8.314 J K ⁻¹ mol ⁻¹ )

MHT CET Medical 2026 Solution View → 34

Consider the reversible processes for 1.0 mol of an ideal gas as shown in the figure. Processes 2 and 4 are adiabatic. w₁ , w₂ , w₃ and w₄ represent work done (in calories) in the

NEET 2026 Solution View → 35

Consider the following reaction : 2 A (g) + B (g) 2 D (g) U^ = -10 kJ mol ⁻¹ and S^ = -44 J K ⁻¹ at 298 K. Identify the correct option with G^ for the reaction and spontaneity of t

NEET 2026 Solution View → 36

Two moles of an ideal gas undergo free expansion from 10 L to 100 L at 300 K. The values of S_ system and S_ surroundings are (R is universal gas constant)

NEET 2026 Solution View → 37

At a certain temperature, T (K), during a process, 500 J is absorbed by the system and work of 200 J is done by the system. Then, change in internal energy of the system is :

NEET 2026 Solution View → 38

A protein undergoes reversible thermal denaturation from its initial state N to denatured state D according to N D . At 60 °C, the concentrations of both N and D are equal at equil

NEET 2026 Solution View → 39

C ( ~s )+2 H ₂( ~g ) CH ₄( ~g ) ; H =-74.8 ~kJ ~mol ⁻¹ Which of the following diagrams gives an accurate representation of the above reaction? [ R reactants; P products ]

NEET 2025 Solution View → 40

The standard heat of formation, in kcal / mol ^ of Ba ²⁺ is : [Given : standard heat of formation of SO ₄²⁻ ion (aq) =-216 kcal / mol , Standard heat of crystallisation of BaSO ₄(

NEET 2025 Solution View → 41

Choose the correct statement for the work done in the expansion and heat absorbed or released when 5 litres of an ideal gas at 10 atmospheric pressure isothermally expands into vac

NEET 2024 Solution View → 42

Match List-I with List-II: Choose the correct answer from the options given below:

NEET 2024 Solution View → 43

For an endothermic reaction: (A) qp _ p is negative. (B) _r H is positive. (C) _r H is negative. (D) q _ p is positive. Choose the correct answer from the options given below:

NEET 2024 Solution View → 44

In which of the following processes entropy increases? A. A liquid evaporates to vapour. B. Temperature of a crystalline solid lowered from 130 K to 0 K . C. 2 NaHCO _ 3( ~s ) Na ₂

NEET 2024 Solution View → 45

Match List I with List II. Choose the correct answer from the options given below:

NEET 2024 Solution View → 46

The work done during reversible isothermal expansion of one mole of hydrogen gas at 25^ C from pressure of 20 atmosphere to 10 atmosphere is (Given R =2.0 cal K ⁻¹ ~mol ⁻¹ )

NEET 2024 Solution View → 47

For the following reaction at 300 K A ₂( ~g )+3 ~B ₂( ~g ) 2 AB ₃( ~g ) the enthalpy change is +15 kJ then the internal energy change is:

NEET 2024 Solution View → 48

Consider the following reaction: 2 H ₂( ~g )+ O ₂( ~g ) 2 H ₂ O ( g ) _ r H ^ =-483.64 ~kJ . What is the enthalpy change for decomposition of one mole of water? (Choose the right o

NEET 2023 Solution View → 49

Which amongst the following options is the correct relation between change in enthalpy and change in internal energy?

NEET 2023 Solution View → 50

The equilibrium concentrations of the species in the reaction A + B ⇋ C + D are 2 , 3 , 10   and   6   mol   L - 1 respectively at 300 K . ∆ G &#872

NEET 2023 Solution View → 51

Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R: Assertion A: In equation ∆ r G = - nFE cell value of ∆ r G depends

NEET 2023 Solution View → 52

One mole of an ideal gas at 300 ~K is expanded isothermally from 1 ~L to 10 ~L volume. U for this process is (Use R =8.314 ~J ~K ⁻¹ ~mol ⁻¹ )

NEET 2022 Solution View → 53

Which of the following p - V curve represents maximum work done?

NEET 2022 Solution View → 54

For irreversible expansion of an ideal gas under isothermal condition, the correct option is:

NEET 2021 Solution View → 55

Which one among the following is the correct option for right relationship between C p and C v for one mole of ideal gas?

NEET 2021 Solution View → 56

If for a certain reaction Δ r H is 30   kJmol - 1 at 450 K , the value of Δ r S (in JK - 1 mol - 1 ) for which the same reaction will be spontaneous at the same temp

NEET 2020 Solution View → 57

For the reaction, 2 Cl g → Cl 2 g , the correct option is

NEET 2020 Solution View → 58

At standard conditions, if the change in the enthalpy for the following reaction is - 109   kJmol - 1 H 2 ( g ) + Br 2 ( g ) → 2 HBr ( g ) Given that bond energy of H 2

NEET 2020 Solution View → 59

The correct option for free expansion of an ideal gas under adiabatic condition is

NEET 2020 Solution View → 60

Hydrolysis of sucrose is given by the following reaction. Sucrose + H 2 O ⇌ Glucose + Fructose If the equilibrium constant K C is 2 × 10 13 at 300   K , the value o

NEET 2020 Solution View → 61

In isolated system, find the condition for spontaneous reaction.

AIIMS 2019 Solution View → 62

At 25^ C , when 1 mole of butane is heated, CO ₂ and liquid H ₂ O are formed, then the work done is

AIIMS 2019 Solution View → 63

Reaction, A B+3 C at 25^ C is in equilibrium. If equilibrium constant and Gibbs' free energy for this reaction are y and x respectively, then the Gibbs' free energy for reaction, 1

AIIMS 2019 Solution View → 64

Assertion : U is a state function. Reason : T is an intensive property.

AIIMS 2019 Solution View → 65

Assertion : The graph between P v / s 1 / V is a straight line. Reason : At constant temperature, P 1 / V .

AIIMS 2019 Solution View → 66

What is the value of for mono atomic gas (ideal gas)?

JIPMER 2019 Solution View → 67

If equilibrium constant is 2.6 10^8 at 298 K then find the value of G ^ .

JIPMER 2019 Solution View → 68

An ideal 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 . The work done on the gas is

NEET 2019 Solution View → 69

Reversible expansion of an ideal gas under isothermal and adiabatic conditions are as shown in the figure. A B Isothermal expansion A C Adiabatic expansion Which of the following o

NEET 2019 Solution View → 70

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 t

NEET 2019 Solution View → 71

In which case change in entropy is negative?

NEET 2019 Solution View → 72

1 mole of an ideal gas expands isothermally reversibly from 2 litre to 4 litre and 3 moles of the same gas expands from 2 litre to x litre and doing same work, what is ' x '?

AIIMS 2018 Solution View → 73

If one monoatomic gas is expanded adibatically from 2 ~L to 10 ~L at 1 ~atm external pressure then the value of U (in atm L ) is

AIIMS 2018 Solution View → 74

What is the entropy change in 2 ~mol ~N ₂ , when its temperature is taken from 400 ~K to 800 ~K , at constant pressure?

AIIMS 2018 Solution View → 75

Assertion : Addition of Q and w gives U . Reason : Addition of two path functions cannot give state function.

AIIMS 2018 Solution View → 76

Which of the following are extensive properties?

AIIMS 2018 Solution View → 77

Conversion of oxygen into ozone is non-spontaneous at

JIPMER 2018 Solution View → 78

In adiabatic conditions, 2 mole of CO ₂ gas at 300 K is expanded such that its volume becomes 27 times. Then, the work done is ( C _ V =6 cal mol ⁻¹ . and . =1.33 )

JIPMER 2018 Solution View → 79

Given that, for the reaction, 1 2 H ₂+ 1 2 Cl ₂ HCl aligned & H _ f ( HCl )=-93 ~kJ / mol & B.E ( H ₂ )=434 ~kJ / mol & B.E ( Cl ₂ )=242 ~kJ / mol aligned The bond dissociation ene

JIPMER 2018 Solution View → 80

For the following reaction, Then, K _ e 0 for this equilibrium is

JIPMER 2018 Solution View → 81

The bond dissociation energies of X 2   Y 2 and XY are in the ratio of 1   : 0 .5   : 1 .   ΔH for the formation of XY is - 200   kJ   mol - 1 .

NEET 2018 Solution View → 82

The heat is liberated when 1.89 ~g of benzoic acid is burnt in a bomb calorimeter at 25^ C and it increases the temperature of 18.94 ~kg of water by 0.632^ C . If the specific heat

AIIMS 2017 Solution View → 83

Assertion : Spontaneous process is an irreversible process and may be reversed by some external agency. Reason : Decrease in enthalpy is a contributory factor for spontaneity.

AIIMS 2017 Solution View → 84

When the heat of reaction at constant pressure is -2.5 10^3 cal and entropy change is 7.4 cal deg ⁻¹ at 25^ C , the reaction is predicted as

JIPMER 2017 Solution View → 85

The energy released when 6 moles of octane is burnt in air will be [Given, H_f^ for CO ₂(g) , H ₂ O ( g ) and C ₈ H ₁₈( l ) , respectively are -490 , -240 and +160 ~J / mol ]

JIPMER 2017 Solution View → 86

For a given reaction, Δ H = 35.5 k J m o l - 1 and Δ S = 83.6 J K - 1 m o l - 1 . The reaction is spontaneous at : (Assume that Δ H and Δ S do not vary with temperature)

NEET 2017 Solution View → 87

A gas is allowed to expand in a well-insulated container against a constant external pressure of   2 . 5   atm from an initial volume of 2 . 50   L to a final volume

NEET 2017 Solution View → 88

The heat liberated when 1.89 ~g of benzoic acid is burnt in a bomb calorimeter at 25^ C and it increases the temperature of 18.94 ~kg of water by 0.632^ C . If the specific heat of

AIIMS 2016 Solution View → 89

Assertion : Heat of neutralisation for both H ₂ SO ₄ and HCl with NaOH is 53.7 ~kJ ~mol ⁻¹ . Reason : Both HCl and H ₂ SO ₄ are strong acids.

AIIMS 2016 Solution View → 90

Assertion : A reaction which is spontaneous and accompanied by decrease of randomness must be exothermic. Reason : All exothermic reactions are accompanied by decrease of randomnes

AIIMS 2016 Solution View → 91

A hypothetical reaction A 2 B proceeds through the following sequence of steps I. A C ; _r H=q₁ II. C D ; _r H=q₂ III. 1 2 D B ; _r H=q₃ The heat of hypothetical reaction is

JIPMER 2016 Solution View → 92

At 27^ C , one mole of an ideal gas is compressed isothermally and reversibly from a pressure of 2 atm to 10 atm . Choose the correct option from the following.

JIPMER 2016 Solution View → 93

The correct thermodynamic conditions for the spontaneous reaction at all temperatures is:

NEET 2016 Solution View → 94

For a sample of perfect gas, when its pressure is changed isothermally from p i to p f , the entropy change is given by

NEET 2016 Solution View → 95

Consider the following liquid - vapour equilibrium. L i q u i d ⇌ V a p o u r Which of the following relations is correct?

NEET 2016 Solution View → 96

For the reaction of one mole of zinc dust with one mole of sulphuric acid in a bomb calorimeter, U and w correspond to

AIIMS 2015 Solution View → 97

If for a given substance, melting point is T_B and freezing point is T_A then correct variation of entropy by graph between entropy change and temperature is

JIPMER 2015 Solution View → 98

What would be the heat released when an aqueous solution containing 0.5 mole of HNO ₃ is mixed with 0.3 mole of OH ⁻ ? (enthalpy of neutralisation is -57.1 kJ )

JIPMER 2015 Solution View → 99

Which of the following statements is correct for a reversible process in the state of equilibrium?

NEET 2015 Solution View → 100

The heat of combustion of carbon to C O 2 is   - 393 . 5   kJ / mol . The heat released upon the formation of 35 . 2   g of C O 2 from carbon and oxygen gas is

NEET 2015 Solution View → 101

A diatomic gas at pressure P , compressed adiabatically to half of its volume, what is the final pressure?

AIIMS 2014 Solution View → 102

If a gas expands at constant temperature indicates that

JIPMER 2014 Solution View → 103

The standard enthalpies of formation of A ( NH ₃ ), B ( CO ₂ ), C( HI ) and D ( SO ₂ ) are -46.19 , -393.4,+24.94 and -296.9 ~kJ ~mol ⁻¹ respectively. The increasing order of their

JIPMER 2014 Solution View → 104

For the reaction: X 2 O 4 l → 2 X O 2 g ∆ U = 2 .1   k   cal ,   ∆ S = 20   cal   K - 1 at 300   K Hence, ∆ G is:

NEET 2014 Solution View → 105

Using the Gibbs change, ∆ G o = + 63.3   k J , for the following reaction, A g 2 C O 3 g   ⇌ 2 A g + a q + C O 3 2 - a q the K s p of A g 2 C O 3 s in water a

NEET 2014 Solution View → 106

Energy of activation of forward reaction for an endothermic process is 50 ~kJ . If enthalpy change for forward reaction is 20 ~kJ then enthalpy change for backward reaction will be

AIIMS 2013 Solution View → 107

Assertion : Bond dissociation energy is F ₂> Cl ₂ Reason : Cl ₂ has more electronic repulsion than F ₂ .

AIIMS 2013 Solution View → 108

Assertion : For an isolated system, q is zero. Reason : In an isolated system, change in U and V is zero.

AIIMS 2013 Solution View → 109

Assertion : A process is called adiabatic if the system does not exchange heat with the surroundings. Reason : It does not not involve increase or decrease in temperature of the sy

AIIMS 2013 Solution View → 110

Which thermodynamic parameter is not a state function?

AIIMS 2013 Solution View → 111

Assertion : Entropy of system increases for a spontaneous reaction. Reason : Enthalpy of reaction always decreases for spontaneous reaction.

AIIMS 2013 Solution View → 112

For the process to occur under adiabatic conditions, the correct condition is

JIPMER 2013 Solution View → 113

3 2 O ₂(g) O ₃(g) ; K_p for this reaction is 2.47 10⁻²⁹ . At 298 ~K , _r G^ for conversion of oxygen to ozone will be

JIPMER 2013 Solution View → 114

Three thermochemical equation are given below: (i) kJJ mol ⁻¹ C _ (graphite) + O _ 2( ~g ) CO _ 2(g) H ^ =x (iii) CO _ ( gJ ) +1 / 2 O _ 2( gk CO _ 2( ~g ) i H ^ = z Based on the a

NEET 2013 Solution View → 115

When 5 litres of a gas mixture of methane and propane is perfectly combusted at 0^ C and 1 atmosphere, 16 litres of oxygen at the same temperature and pressure is consumed. The amo

NEET 2013 Solution View → 116

At equilibrium which is correct?

AIIMS 2012 Solution View → 117

Bond dissociation energy of CH ₄ is 360 ~kJ / mol and C ₂ H ₆ is 620 ~kJ / mol . Then bond dissociation energy of C - C bond is

AIIMS 2012 Solution View → 118

The enthalpy of fusion of water is 1.435 kcal / mol . The molar entropy change for the melting of ice at 0^ C is

NEET 2012 Solution View → 119

Standard enthalpy of vaporisation _ vap H^ s 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 va

NEET 2012 Solution View → 120

In which of the following reactions, standard reaction entropy changes ( S^ ) is positive and standard Gibb's energy change ( G^ ) decreases sharply with increasing temperature?

NEET 2012 Solution View →
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