NEET UG · Chemistry · Class 11

Thermodynamics: NEET previous year questions

32 questions in ten years of NEET, asked in 10 of 10 years. Here is what this chapter tests and how.

Asked in 10 years: 32; 10 of 10 papers
10-year average: 3.1; a paper · 3.9 since 2024 +1.1
Typical range: 2–4; questions a paper; fewest 2, most 5
Weighted estimate: 3.5; model, recent papers count more · about 14 marks

Typical range (fact)
10-year average (fact)
Weighted estimate (model)

Typical range: questions per paper in the middle eight of the ten papers, leaving out the single highest and lowest year (about the 10th to 90th percentile), each paper scaled to 180 questions. The ten-year average and the range are historical fact. The weighted estimate is a model: each paper's share, with recent papers counting more (half-life three years), and dropped syllabus removed. It is a guide to effort, not a forecast.

What to do

How to spend time on Thermodynamics

Priority

Must do

Among the chapters that held the first half of all NEET questions in ten years. How bands are set

Past questions: 32in 10 of 10 papers
Study plan gives it: 23 hover 12 months; 18 h over 6

Study this chapter →Practise →

Ideas asked most often

Entropy Change Prediction3×
First Law in Isobaric Processes2×
Slopes on P-V Diagrams2×

282 of the 325 ideas in Lumi’s map of this chapter have not been asked or touched in ten years. New questions often come from ideas like these, so learn the whole chapter, not just the list above.

Questions per year

Kind of question

SHARE OF 10 YEARS

Calculation44%
Figure-based22%
Concept16%
Recall9%
Match the lists6%
Application3%

Most common asks: numerical (16); ratio of work to heat in isobaric process of monatomic gas (1); identify thermodynamic quantities for process (1).

Profile

This chapter in numbers

Where it ranks, how steady it is, and what it costs to study.

Rank, all NEET chapters: #10; of 80 by weighted estimate
Rank in Chemistry: #1; of 21 chapters
Share of the paper: 1.7%; ten-year average
Busiest year: 2026; 5 questions
Year to year: Some swing; varies by about 1.0 questions
Long-run direction: +0.01; questions per paper, per year
Easy questions: 50%; 65% of ideas rated hard
With a figure: 25%; graph, diagram or structure
Study time: 23 h; 18 h on a 6-month plan
Marks per study hour: 0.60; #30 of 80 chapters
Foundation for others: 54%; of its ideas are used in other chapters

Difficulty, year by year

Each question rated easy, medium or hard against NCERT.

20174
20184
20193
20203
20212
20222
20232
20244
20253
20265

Easy
Medium
Hard

What it asks you to do

SHARE OF QUESTIONS

Calculation41%
Concept16%
Data or graph16%
Recall13%
Multi-step9%
Application3%
Figure reading3%

Coverage

How much of the chapter NEET has used

We split the chapter into 325 ideas. In ten years NEET built a question around 20 of them. Most of the chapter has never been asked, which is why learning it whole beats memorising past questions.

Asked as the main idea: 20
Touched on in a question: 23
Never asked: 282

Topics

What repeats, topic by topic

Questions per topic in each year's paper. Topics that come every year are worth learning first.

Laws of Thermodynamics · Every year10
12111112
First Law of Thermodynamics · Every year8
1111121
Gibbs Free Energy · Every year7
111112
Enthalpy and Hess's Law · Most years4
112
Carnot Engine · Most years3
111

’17’18’19’20’21’22’23’24’25’26

Topic	2017	’18	2019	’20	2021	’22	2023	’24	2025	’26	Total
Laws of ThermodynamicsEvery year	1	2	1	1	·	1	·	1	1	2	10
First Law of ThermodynamicsEvery year	1	·	1	1	1	1	·	2	·	1	8
Gibbs Free EnergyEvery year	1	·	1	1	1	·	·	1	·	2	7
Enthalpy and Hess's LawMost years	·	1	·	·	·	·	1	·	2	·	4
Carnot EngineMost years	1	1	·	·	·	·	1	·	·	·	3

02+questions in that year’s paper

Drill down

Topic, idea, question

Open a topic to see every idea NEET tested inside it, then open an idea to read the questions. Each row shows its ten papers.

topicAskedShareYears’17’18’19’20’21’22’23’24’25’26

Open10 · 31%31%8/1022
8 ideas inside
- Repeated2 · 20%20%2/10
- Repeated2 · 20%20%2/10
- 1 · 10%10%1/10
- 1 · 10%10%1/10
- 1 · 10%10%1/10
- 1 · 10%10%1/10
- 1 · 10%10%1/10
- 1 · 10%10%1/10
Open8 · 25%25%7/102
Open7 · 22%22%6/102
Open4 · 13%13%3/102
Open3 · 9%9%3/10

Squares are the ten papers, 2017 to 2026; darker means more questions. Share is of the level above.

Ideas

The exact ideas NEET has asked

Inside the topics, 28 different ideas were tested. These came more than once, or are new since 2024.

Entropy Change Prediction3×
signs of enthalpy and entropy change
First Law in Isobaric Processes2×
ratio of work to heat in isobaric process of monatomic gas
Slopes on P-V Diagrams2×
identify adiabatic curve on p-v graph
Gibbs Energy and EquilibriumNew1×
numerical
Entropy of Free ExpansionNew1×
numerical
Work in Cyclic ProcessesNew1×
true statement selection on thermodynamic cycle
Adiabatic Work CalculationNew1×
numerical
First Law in Cyclic ProcessesNew1×
numerical
Reaction Enthalpy from Energy ProfilesNew1×
graph interpretation of reaction enthalpy
Hess's Law ApplicationNew1×
numerical
Thermodynamic Process TypesNew1×
match list on thermodynamic processes
Reversible Isothermal WorkNew1×
numerical
Work and First Law from P-V GraphsNew1×
numerical

Idea	Times	Usually asked as
Entropy Change Predictionsigns of enthalpy and entropy change	3	One-line MCQ
First Law in Isobaric Processesratio of work to heat in isobaric process of monatomic gas	2	Figure-based
Slopes on P-V Diagramsidentify adiabatic curve on p-v graph	2	Figure-based
Gibbs Energy and Equilibriumnumerical	1	NumericalNew
Entropy of Free Expansionnumerical	1	NumericalNew
Work in Cyclic Processestrue statement selection on thermodynamic cycle	1	Figure-basedNew
Adiabatic Work Calculationnumerical	1	NumericalNew
First Law in Cyclic Processesnumerical	1	Figure-basedNew
Reaction Enthalpy from Energy Profilesgraph interpretation of reaction enthalpy	1	Figure-basedNew
Hess's Law Applicationnumerical	1	NumericalNew
Thermodynamic Process Typesmatch list on thermodynamic processes	1	Match the listsNew
Reversible Isothermal Worknumerical	1	NumericalNew
Work and First Law from P-V Graphsnumerical	1	Figure-basedNew

Every question

Thermodynamics questions, year by year

The opening words of each question as it appeared in the official paper.

NEET 20265 questions

Q17In an adiabatic expansion, the temperature of one mole of an ideal monatomic gas ( $\gamma=5/3$ ) decreases from 60K to 50K. The work done…Numerical
Q39One mole of an ideal monatomic gas undergoes a cyclic process as shown in the figure. The total heat supplied to the gas is :Figure-based · figure
Q59Two moles of an ideal gas undergo free expansion from 10 L to 100 L at 300 K. The values of $\Delta S_{system}$ and…Numerical
Q69Consider the reversible processes for 1.0 mol of an ideal gas as shown in the figure. [Figure: Processes 2 and 4 are adiabatic] $w_1$ ,…Figure-based · figure
Q74A protein undergoes reversible thermal denaturation from its initial state N to denatured state D according to N $\rightleftharpoons$ D.…Numerical

NEET 20253 questions

Q41Two gases $A$ and $B$ are filled at the same pressure in separate cylinders with movable pistons of radius $r_A$ and $r_B$ , respectively.…Numerical
Q65 $C(s) + 2H_2(g) \to CH_4(g)$ ; $\Delta H = -74.8$ kJ mol $^{-1}$ Which of the following diagrams gives an accurate representation of the…Figure-based · figure
Q85The standard heat of formation, in kcal/mol of $Ba^{2+}$ is : [Given : standard heat of formation of $SO_4^{2-}$ ion (aq) = – 216…Numerical

NEET 20244 questions

Q7A thermodynamic system is taken through the cycle $abcda$ . The work done by the gas along the path $bc$ is :Figure-based · figure
Q53Match List I with List II. List I (Process) | List II (Conditions) A. Isothermal process | I. No heat exchange B. Isochoric process | II.…Match the lists
Q61In which of the following processes entropy increases? A. A liquid evaporates to vapour. B. Temperature of a crystalline solid lowered…Other
Q91The work done during reversible isothermal expansion of one mole of hydrogen gas at 25°C from pressure of 20 atmosphere to 10 atmosphere…Numerical

NEET 20232 questions

Q26A Carnot engine has an efficiency of 50% when its source is at a temperature 327° C. The temperature of the sink is :Numerical
Q88Which amongst the following options is the correct relation between change in enthalpy and change in internal energy?One-line MCQ

NEET 20222 questions

Q24An ideal gas undergoes four different processes from the same initial state as shown in the figure below. Those processes are adiabatic,…Figure-based · figure
Q75Which of the following p-V curve represents maximum work done ?Figure-based · figure

NEET 20212 questions

Q75Which one among the following is the correct option for right relationship between $C_P$ and $C_V$ for one mole of ideal gas ?One-line MCQ
Q96For irreversible expansion of an ideal gas under isothermal condition, the correct option is :One-line MCQ

NEET 20203 questions

Q104The correct option for free expansion of an ideal gas under adiabatic condition is :One-line MCQ
Q127For the reaction, $\mathrm{2Cl(g) \to Cl_2(g)}$ , the correct option is :One-line MCQ
Q141Two cylinders A and B of equal capacity are connected to each other via a stop cock. A contains an ideal gas at standard temperature and…One-line MCQ

NEET 20193 questions

Q40In which of the following processes, heat is neither absorbed nor released by a system ?One-line MCQ
Q51Under 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…Numerical
Q86In which case change in entropy is negative ?One-line MCQ

NEET 20184 questions

Q1The volume (V) of a monatomic gas varies with its temperature (T), as shown in the graph. The ratio of work done by the gas, to the heat…Figure-based · figure
Q4The efficiency of an ideal heat engine working between the freezing point and boiling point of water, isNumerical
Q45A sample of 0.1 g of water at 100°C and normal pressure ( $1.013\times10^{5}$ Nm $^{-2}$ ) requires 54 cal of heat energy to convert to steam…Numerical
Q85The bond dissociation energies of $\mathrm{X_2}$ , $\mathrm{Y_2}$ and XY are in the ratio of 1 : 0.5 : 1. $\Delta H$ for the formation of…Numerical

NEET 20174 questions

Q16Thermodynamic processes are indicated in the following diagram. Match the following Column-1 | Column-2 P. Process I | a. Adiabatic Q.…Match the lists · figure
Q27A carnot engine having an efficiency of $\frac{1}{10}$ as heat engine, is used as a refrigerator. If the work done on the system is 10 J,…Numerical
Q60A 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…Numerical
Q77For a given reaction, $\Delta H$ = 35.5 kJ $\mathrm{mol^{-1}}$ and $\Delta S$ = 83.6 J $\mathrm{K^{-1}}$ $\mathrm{mol^{-1}}$ . The reaction…Numerical

Questions from the official NEET UG papers published by NTA (CBSE before 2019). Topic and idea tags, counts and notes are Lumi’s.

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