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Chemistry - Thermodynamics (C)

Practise 87 NEET 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 NEET tests.

Thermodynamics (C) has been asked in 25 of the 39 years of NEET papers analysed (1988–2026), with 87 questions in all. 26% of them were easy, 49% moderate and 24% tough. Most of its questions came from 2024, with 7 questions that year. In the last three years (2024–2026) it had 14 questions across 13 papers, about 1.1 per paper.

The chapter's 5 topics are not weighted equally: Laws of Thermochemistry and Enthalpy Change (27 questions, 31%), First Law and Basic Fundamentals of Thermodynamics (23 questions, 26%), and Third law of thermodynamics (21 questions, 24%) have been asked the most. Over the last five years the most frequent topics have been First Law and Basic Fundamentals of Thermodynamics (10), Laws of Thermochemistry and Enthalpy Change (5), and Entropy and Second law of thermodynamics (3). Laws of Thermochemistry and Enthalpy Change has produced the most tough questions (10).

  1. 1Consider the following reaction : kJ mol and J K at K. Identify the correct option with for the reaction and spontaneity of the reaction at 2026 (Cancelled)First Law and Basic Fundamentals of Thermodynamics
  2. 2At a certain temperature, (K), during a process, J is absorbed by the system and work of J is done by the system. Then, change in internal e2026 (Cancelled)First Law and Basic Fundamentals of Thermodynamics
  3. 3Two moles of an ideal gas undergo free expansion from L to L at K. The values of and are (R is universal gas constant)2026 (Re-NEET)Entropy and Second law of thermodynamics
  4. 4Consider the reversible processes for mol of an ideal gas as shown in the figure. Processes 2 and 4 are adiabatic. , , and represent work do2026 (Re-NEET)First Law and Basic Fundamentals of Thermodynamics
  5. 5A protein undergoes reversible thermal denaturation from its initial state to denatured state according to . At °C, the concentrations of bo2026 (Re-NEET)Entropy and Second law of thermodynamics
  6. 6Which of the following diagrams gives an accurate representation of the above reaction? reactants; products2025Laws of Thermochemistry and Enthalpy Change
  7. 7The standard heat of formation, in is : [Given : standard heat of formation of ion (aq) , Standard heat of crystallisation of , standard hea2025Laws of Thermochemistry and Enthalpy Change
  8. 8Match List I with List II. Choose the correct answer from the options given below:2024First Law and Basic Fundamentals of Thermodynamics
  9. 9In which of the following processes entropy increases? A. A liquid evaporates to vapour. B. Temperature of a crystalline solid lowered from 2024Entropy and Second law of thermodynamics
  10. 10The work done during reversible isothermal expansion of one mole of hydrogen gas at from pressure of 20 atmosphere to 10 atmosphere is (Give2024First Law and Basic Fundamentals of Thermodynamics
  11. 11Choose the correct statement for the work done in the expansion and heat absorbed or released when 5 litres of an ideal gas at 10 atmospheri2024 (Re-NEET)First Law and Basic Fundamentals of Thermodynamics
  12. 12For an endothermic reaction: (A) is negative. (B) is positive. (C) is negative. (D) is positive. Choose the correct answer from the options 2024 (Re-NEET)Laws of Thermochemistry and Enthalpy Change
  13. 13Match List-I with List-II: Choose the correct answer from the options given below:2024 (Re-NEET)Laws of Thermochemistry and Enthalpy Change
  14. 14For the following reaction at 300 K the enthalpy change is +15 kJ then the internal energy change is:2024 (Re-NEET)First Law and Basic Fundamentals of Thermodynamics
  15. 15Given 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 c2023 (All India)System and surrounding
  16. 16Which amongst the following options is the correct relation between change in enthalpy and change in internal energy?2023 (All India)First Law and Basic Fundamentals of Thermodynamics
  17. 17The 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 for the r2023 (All India)Third law of thermodynamics
  18. 18Consider the following reaction: . What is the enthalpy change for decomposition of one mole of water? (Choose the right option).2023 (Manipur)Laws of Thermochemistry and Enthalpy Change
  19. 19Which of the following p - V curve represents maximum work done?2022 (Phase 1)First Law and Basic Fundamentals of Thermodynamics
  20. 20One mole of an ideal gas at is expanded isothermally from to volume. for this process is (Use )2022 (Phase 2)First Law and Basic Fundamentals of Thermodynamics
  21. 21For irreversible expansion of an ideal gas under isothermal condition, the correct option is:2021First Law and Basic Fundamentals of Thermodynamics
  22. 22Which one among the following is the correct option for right relationship between C p and C v for one mole of ideal gas?2021First Law and Basic Fundamentals of Thermodynamics
  23. 23For the reaction, 2 Cl g Cl 2 g , the correct option is2020 (Phase 1)Entropy and Second law of thermodynamics
  24. 24The correct option for free expansion of an ideal gas under adiabatic condition is2020 (Phase 1)First Law and Basic Fundamentals of Thermodynamics
  25. 25Hydrolysis 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 32020 (Phase 1)Third law of thermodynamics
  26. 26If for a certain reaction r H is 30 kJmol - 1 at 450 K , the value of r S (in JK - 1 mol - 1 ) for which the same reaction will be spontaneo2020 (Phase 2)Entropy and Second law of thermodynamics
  27. 27At 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 ) Given2020 (Phase 2)Laws of Thermochemistry and Enthalpy Change
  28. 28Under 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 2019 (All India)First Law and Basic Fundamentals of Thermodynamics
  29. 29In which case change in entropy is negative?2019 (All India)Entropy and Second law of thermodynamics
  30. 30An ideal gas expands isothermally from to at against a constant pressure of . The work done on the gas is2019 (Odisha)First Law and Basic Fundamentals of Thermodynamics
  31. 31Reversible expansion of an ideal gas under isothermal and adiabatic conditions are as shown in the figure. Isothermal expansion Adiabatic ex2019 (Odisha)First Law and Basic Fundamentals of Thermodynamics
  32. 32The bond dissociation energies of X 2 Y 2 and XY are in the ratio of 1 : 0 .5 : 1 . H for the formation of XY is - 200 kJ mol - 1 . What wil2018Laws of Thermochemistry and Enthalpy Change
  33. 33A 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 2017First Law and Basic Fundamentals of Thermodynamics
  34. 34For 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 2017Third law of thermodynamics
  35. 35The correct thermodynamic conditions for the spontaneous reaction at all temperatures is:2016 (Phase 1)Third law of thermodynamics
  36. 36Consider the following liquid - vapour equilibrium. L i q u i d V a p o u r Which of the following relations is correct?2016 (Phase 1)Laws of Thermochemistry and Enthalpy Change
  37. 37For a sample of perfect gas, when its pressure is changed isothermally from p i to p f , the entropy change is given by2016 (Phase 2)Entropy and Second law of thermodynamics
  38. 38Which of the following statements is correct for a reversible process in the state of equilibrium?2015 (Phase 1)Third law of thermodynamics
  39. 39The 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 2015 (Phase 2)Laws of Thermochemistry and Enthalpy Change
  40. 40Using 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 2014Third law of thermodynamics
  41. 41For 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:2014Third law of thermodynamics
  42. 42When 5 litres of a gas mixture of methane and propane is perfectly combusted at and 1 atmosphere, 16 litres of oxygen at the same temperatur2013 (Karnataka)Laws of Thermochemistry and Enthalpy Change
  43. 43Three thermochemical equation are given below: (i) (iii) Based on the above equations, find out which of the relationship given below is cor2013 (Karnataka)Laws of Thermochemistry and Enthalpy Change
  44. 44In which of the following reactions, standard reaction entropy changes is positive and standard Gibb's energy change decreases sharply with 2012 (Screening)Third law of thermodynamics
  45. 45The enthalpy of fusion of water is . The molar entropy change for the melting of ice at is2012 (Screening)Entropy and Second law of thermodynamics
  46. 46Standard enthalpy of vaporisation for water at is . The internal energy of vaporisation of water at (in is (Assume water vapour to behave li2012 (Screening)Laws of Thermochemistry and Enthalpy Change
  47. 47Consider the following processes For will be2011 (Mains)Laws of Thermochemistry and Enthalpy Change
  48. 48Enthalpy change for the reaction, The dissociation energy of bond is2011 (Screening)Laws of Thermochemistry and Enthalpy Change
  49. 49Which of the following is correct option for free expansion of an ideal gas under adiabatic condition?2011 (Screening)First Law and Basic Fundamentals of Thermodynamics
  50. 50If the enthalpy change for the transition of liquid water to steam is at , the entropy change for the process would be2011 (Screening)Laws of Thermochemistry and Enthalpy Change

Frequently Asked Questions

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

This chapter includes 87 questions compiled from NEET papers spanning 2002 to 2026.

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

These are NEET questions specifically for the Thermodynamics (C) chapter. Questions from other exams like AIIMS or JIPMER are organised separately under their respective exam sections.

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

Thermodynamics (C) has appeared in 25 of the 25 years of NEET papers covered here, with 87 questions across 37 papers - about 2 per paper it appears in.

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

Of the 87 questions analysed for this chapter, 26% are easy, 49% moderate and 24% tough. 2024 had the most, with 7 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 - 27 questions (31%)
  • First Law and Basic Fundamentals of Thermodynamics - 23 questions (26%)
  • Third law of thermodynamics - 21 questions (24%)
  • Laws of Thermochemistry and Enthalpy Change has produced the most tough questions (10).
6.Is Thermodynamics (C)'s weightage in NEET going up or down?

Across all 37 papers analysed, Thermodynamics (C) has averaged about 2.4 questions per paper. In the last three years (2024–2026), that average has fallen, at about 1.1 questions per paper. Use the year-wise numbers on this page for the exact trend before you decide how much time to give it.