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Chemistry - Thermodynamics (C)

Practise 264 JEE Main previous year questions on Thermodynamics (C), compiled from papers spanning 2002 to 2026. Each question is pulled directly from the actual exam paper it appeared in, so you're practising in the exact style and difficulty JEE Main tests.

Thermodynamics (C) has been asked in 25 of the 25 years of JEE Main papers analysed (2002–2026), with 264 questions in all. 26% of them were easy, 56% moderate and 18% tough. Most of its questions came from 2025, with 32 questions that year. In the last three years (2024–2026) it had 66 questions across 49 papers, about 1.3 per paper.

The chapter's 6 topics are not weighted equally: Laws of Thermochemistry and Enthalpy Change (100 questions, 38%), First Law and Basic Fundamentals of Thermodynamics (76 questions, 29%), and Third law of thermodynamics (49 questions, 19%) have been asked the most. Laws of Thermochemistry and Enthalpy Change has also led over the last five years, with 53 questions. Laws of Thermochemistry and Enthalpy Change has produced the most tough questions (22).

  1. 1Consider the reaction The magnitude of enthalpy change for the reaction in kJ mol is ________. (Nearest integer) Given: kJ mol kJ mol kJ mol08 Apr, 2026 (E)Laws of Thermochemistry and Enthalpy Change
  2. 2Arrange the following isothermal processes in order of the magnitude of the work ( ) involved between states and . A. Expansion in single st06 Apr, 2026 (M)First Law and Basic Fundamentals of Thermodynamics
  3. 3Consider the reaction at K. If and are kJ mol and at the same temperature, then the magnitude of for the reaction in J K mol is _______. (Ne06 Apr, 2026 (M)Third law of thermodynamics
  4. 4Match List - I with List - II. Given and are initial and final volumes respectively. List - I (Isothermal process) List - II (Expression) A.06 Apr, 2026 (E)First Law and Basic Fundamentals of Thermodynamics
  5. 5Consider the following data for the reaction at . The (in kJ mol ) for the reaction is : Compound (kJ mol ) (J mol K )05 Apr, 2026 (E)Laws of Thermochemistry and Enthalpy Change
  6. 6The correct order of molar heat capacities measured at and is :05 Apr, 2026 (E)First Law and Basic Fundamentals of Thermodynamics
  7. 7Given below are two statements: Statement I: For an ideal gas, heat capacity at constant volume is always greater than the heat capacity at 04 Apr, 2026 (M)First Law and Basic Fundamentals of Thermodynamics
  8. 8If g of ethanol is burnt completely in a bomb calorimeter at K, the heat produced is kJ. The of ethanol at K is ______ kJ mol . (Nearest int04 Apr, 2026 (E)Laws of Thermochemistry and Enthalpy Change
  9. 9Consider the following data. (i) kJ/mol (ii) kJ/mol (iii) kJ/mol (iv) kJ/mol The enthalpy of formation of anhydrous solid is :02 Apr, 2026 (M)Laws of Thermochemistry and Enthalpy Change
  10. 10At the transition temperature , and where and are two states of substance . The transition temperature in C when pressure is atm is _______.02 Apr, 2026 (M)Third law of thermodynamics
  11. 11Gas 'A' undergoes change from state 'X' to state 'Y'. In this process, the heat absorbed and work done by the gas is J and J respectively. N02 Apr, 2026 (E)First Law and Basic Fundamentals of Thermodynamics
  12. 12of an ideal gas ' X ' at 600 K and 0.5 MPa undergoes isothermal reversible expansion until pressure of the gas is 0.2 MPa. Which of the foll28 Jan, 2026 (M)First Law and Basic Fundamentals of Thermodynamics
  13. 13The plot of vs gives a straight line. The intercept and slope respectively are (where K is equilibrium constant).28 Jan, 2026 (E)Entropy and Second law of thermodynamics
  14. 14Match the LIST-I with LIST-II \( {array}{|l|l|c|l|} {List-I} & {Isothermal process} \\ & {for ideal gas system} & {List-II} & {Work done } (24 Jan, 2026 (M)First Law and Basic Fundamentals of Thermodynamics
  15. 15is an endothermic reaction occurring in three steps (elementary). (i) (ii) (iii) Which of the following graphs between potential energy ( -a24 Jan, 2026 (M)Laws of Thermochemistry and Enthalpy Change
  16. 16The heat of atomisation of methane and ethane are ' x ' and ' y ' respectively. The longest wavelength of light capable of breaking the bond24 Jan, 2026 (E)Laws of Thermochemistry and Enthalpy Change
  17. 17A cup of water at (system) is placed in a microwave oven and the oven is turned on for one minute during which the water begins to boil. Whi23 Jan, 2026 (M)First Law and Basic Fundamentals of Thermodynamics
  18. 18Match the LIST-I with LIST-II \( {array}{|c|l|c|c|} & {List-I (Thermodynamic Process)} & & {List-II} \\ & & & {(Magnitude in kJ)} \\ A. & {a22 Jan, 2026 (M)First Law and Basic Fundamentals of Thermodynamics
  19. 19If the enthalpy of sublimation of Li is , enthalpy of dissociation of is , ionization enthalpy of Li is , electron gain enthalpy of F is , s22 Jan, 2026 (E)Laws of Thermochemistry and Enthalpy Change
  20. 20Which of the following graphs between pressure ' p ' versus volume ' V ' represents the maximum work done?21 Jan, 2026 (M)First Law and Basic Fundamentals of Thermodynamics
  21. 21Use the following data : \( {array}{|c|c|c|} {Substance } & { _f {H}^{ }(500 {~K})}{ {kJmol}^{-1}} & { {~S}^{ }(500 {~K})}{ {JK}^{-1} {~mol}21 Jan, 2026 (M)Third law of thermodynamics
  22. 22Consider the following data: (methane, g Enthalpy of sublimation of graphite Dissociation enthalpy of The bond enthalpy of bond is given by 21 Jan, 2026 (E)Laws of Thermochemistry and Enthalpy Change
  23. 23Preview not available - open to view this question.08 Apr, 2025 (E)Laws of Thermochemistry and Enthalpy Change
  24. 24Total enthalpy change for freezing of 1 mol of water at to ice at is ____ (Given : )07 Apr, 2025 (M)Laws of Thermochemistry and Enthalpy Change
  25. 25The hydration energies of and are -x and -y respectively. If lattice energy of KCl is -z , then the heat of solution of KCl is :07 Apr, 2025 (E)Laws of Thermochemistry and Enthalpy Change
  26. 26The correct statement amongst the following is :07 Apr, 2025 (E)Laws of Thermochemistry and Enthalpy Change
  27. 27One mole of an ideal gas expands isothermally and reversibly from to at , q and work done in the process respectively are : Given : and04 Apr, 2025 (M)First Law and Basic Fundamentals of Thermodynamics
  28. 28Let us consider a reversible reaction at temperature, T. In this reaction, both and were observed to have positive values. If the equilibriu04 Apr, 2025 (M)Third law of thermodynamics
  29. 29Consider the given data : (a) (b) Choose the correct statement :04 Apr, 2025 (E)Laws of Thermochemistry and Enthalpy Change
  30. 30Which of the following properties will change when system containing solution 1 will become solution 2?03 Apr, 2025 (M)System and surrounding
  31. 31Given : The for is _____ (nearest integer value)03 Apr, 2025 (M)Laws of Thermochemistry and Enthalpy Change
  32. 32A perfect gas having (independent of temperature) undergoes the above transformation from point 1 to point 4. If each step is reversible, th03 Apr, 2025 (E)First Law and Basic Fundamentals of Thermodynamics
  33. 33Given below are two statements : Statement I : When a system containing ice in equilibrium with water (liquid) is heated, heat is absorbed b03 Apr, 2025 (E)Laws of Thermochemistry and Enthalpy Change
  34. 34A sample of n-octane was completely burnt in excess of oxygen in a bomb calorimeter, whose heat capacity is . As a result of combustion reac03 Apr, 2025 (E)Laws of Thermochemistry and Enthalpy Change
  35. 35Two vessels A and B are connected via stopcock. The vessel A is filled with a gas at a certain pressure. The entire assembly is immersed in 02 Apr, 2025 (M)First Law and Basic Fundamentals of Thermodynamics
  36. 36Arrange the following in order of magnitude of work done by the system / on the system at constant temperature : (a) for expansion in infini02 Apr, 2025 (E)First Law and Basic Fundamentals of Thermodynamics
  37. 37Which of the following graphs correctly represents the variation of thermodynamic properties of Haber's process?02 Apr, 2025 (E)Third law of thermodynamics
  38. 38500 J of energy is transferred as heat to 0.5 mol of Argon gas at 298 K and 1.00 atm. The final temperature and the change in internal energ29 Jan, 2025 (M)First Law and Basic Fundamentals of Thermodynamics
  39. 39If (diamond (graphite diamond C (graphite) at constant temperature. Then29 Jan, 2025 (E)Laws of Thermochemistry and Enthalpy Change
  40. 40Ice and water are placed in a closed container at a pressure of 1 atm and temperature 273.15 K . If pressure of the system is increased 2 ti28 Jan, 2025 (M)System and surrounding
  41. 41The formation enthalpies, for and are 220.0 and , respectively, at 298.15 K , and for is at the same temperature. The average bond enthalpy 28 Jan, 2025 (M)Laws of Thermochemistry and Enthalpy Change
  42. 42An ideal gas undergoes a cyclic transformation starting from the point and coming back to the same point by tracing the path as shown in the28 Jan, 2025 (E)First Law and Basic Fundamentals of Thermodynamics
  43. 43Consider the following data : Heat of formation of Heat of formation of Heat of combustion of benzene The heat of formation of benzene is _ 28 Jan, 2025 (E)Laws of Thermochemistry and Enthalpy Change
  44. 44Let us consider an endothermic reaction which is non-spontaneous at the freezing point of water. However, the reaction is spontaneous at boi24 Jan, 2025 (M)Third law of thermodynamics
  45. 45Standard entropies of and are 70,50 and respectively. The temperature in Kelvin at which the reaction will be at equilibrium is_______. (Nea24 Jan, 2025 (M)Third law of thermodynamics
  46. 46Which of the following mixing of 1 M base and 1 M acid leads to the largest increase in temperature?24 Jan, 2025 (E)Entropy and Second law of thermodynamics
  47. 47The heat of formation of is given by :24 Jan, 2025 (E)Laws of Thermochemistry and Enthalpy Change
  48. 48Ice at is heated to become vapor with temperature of at atmospheric pressure. The entropy change associated with this process can be obtaine23 Jan, 2025 (M)Entropy and Second law of thermodynamics
  49. 49The standard enthalpy and standard entropy of decomposition of to are and respectively. The standard free energy change for this reaction at23 Jan, 2025 (M)Third law of thermodynamics
  50. 50The effect of temperature on spontaneity of reactions are represented as :23 Jan, 2025 (E)Laws of Thermochemistry and Enthalpy Change

Frequently Asked Questions

1.How many questions are available for Thermodynamics (C)?

This chapter includes 264 questions compiled from JEE Main papers spanning 2002 to 2026.

2.Are these questions only from JEE Main, or from other exams too?

These are JEE Main questions specifically for the Thermodynamics (C) chapter. Questions from other exams like NTA Abhyas (JEE Main) or JEE Advanced are organised separately under their respective exam sections.

3.Is Thermodynamics (C) an important chapter for JEE Main Chemistry?

Thermodynamics (C) has appeared in 25 of the 25 years of JEE Main papers covered here, with 264 questions across 192 papers - about one per paper it appears in.

4.What is the difficulty level of Thermodynamics (C) questions in JEE Main?

Of the 264 questions analysed for this chapter, 26% are easy, 56% moderate and 18% tough. 2025 had the most, with 32 questions.

5.Which topics in Thermodynamics (C) should I focus on?

These topics have carried the most weightage in Thermodynamics (C):

  • Laws of Thermochemistry and Enthalpy Change - 100 questions (38%)
  • First Law and Basic Fundamentals of Thermodynamics - 76 questions (29%)
  • Third law of thermodynamics - 49 questions (19%)
  • Laws of Thermochemistry and Enthalpy Change has produced the most tough questions (22).
6.Is Thermodynamics (C)'s weightage in JEE Main going up or down?

Across all 192 papers analysed, Thermodynamics (C) has averaged about 1.4 questions per paper. In the last three years (2024–2026), that average has stayed about the same, at about 1.3 questions per paper. Use the year-wise numbers on this page for the exact trend before you decide how much time to give it.