NEET UG · Physics · Kinetic Theory

Kinetic Theory of Gases: NEET previous year questions

14 questions in ten years of NEET, in 10 of 10 papers. Pattern: Every year. Here is how it is asked and which ideas come back.

Asked in 10 years: 14; about 1.4 per paper
Years asked: 10/10; last asked 2026
Chance of a question next paper: 84%; historical rate, how we compute it
Weighted estimate: 1.5; model; history: 1.4 a paper on average, typically 1–2

Key findings

01
Asked in 10 of 10 papers, 14 questions in all: #41 of 204 topics by ten-year total.
02
31% of its questions since 2018 tested an idea never asked before; 3 repeated an idea from the year before.
03
The most repeated idea is Ideal Gas Equation, asked 5 times (2020, 2022, 2024, 2025), usually as “numerical”.
04
NEET has asked 0 of the 5 ideas in this topic; 0 have never been asked, directly or indirectly.
05
Mostly asked as numerical (64%); 36% easy, 0% hard, and up from 1.3 to 1.6 questions a paper since 2024.

Questions per year

Up to 2023: 1.3; per paper
Since 2024: 1.6; +0.4
Usual gap: 1.0 yrs; between papers asking it
Swing: ±0.7; questions, year to year

Recent framings

numerical: number density from mean free path ratio
numerical: vibrational modes from heat capacity ratio
numerical: mass of gas withdrawn from cylinder

Revise first

Ideal Gas Equation (2020 2022 2024 2025); Degrees of Freedom and Internal Energy (2017 2021 2026); Mean Free Path (2020 2026)

How it is asked

Difficulty, format and skill

Across all 14 questions on Kinetic Theory of Gases since 2017.

Difficulty

QUESTIONS

Easy5 · 36%
Medium9 · 64%
Hard0 · 0%

Format

Numerical · 9 Q64%
One-line MCQ · 3 Q21%
Figure-based · 1 Q7%
Match the lists · 1 Q7%

Skill tested

Calculation · 5 Q36%
Multi-step · 4 Q29%
Recall · 3 Q21%
Data or graph · 1 Q7%
Concept · 1 Q7%

Repeats

New idea, or one asked before?

Each column is a paper. Blue questions tested an idea NEET had not asked before; navy ones went back to an idea from an earlier paper. 2017 is the first paper, so everything in it counts as new.

’17’18’19’20’21’22’23’24’25’26

Idea asked for the first time
Idea asked in an earlier paper

Coverage of the topic

NEET has asked 0 of the 5 ideas in this topic. 0 have never been asked yet.

Asked directly0 · 0%
Touched inside another question5 · 100%
Never asked0 · 0%

Ideas come from Lumi’s syllabus map of NCERT. A never-asked idea is not a safe skip: most new questions come from exactly these.

Drill down

Idea, year, question

Every idea NEET tested in this topic, with its ten papers. Open one to read the questions.

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

Repeated5 · 36%36%4/102
- 2025 · Q14
  An oxygen cylinder of volume 30 litre has 18.20 moles of oxygen. After some oxygen is withdrawn from the cylinder, its gauge pressure…
  mediumNumericalAsked the year before
- 2025 · Q29
  A container has two chambers of volumes $V_1$ = 2 litres and $V_2$ = 3 litres separated by a partition made of a thermal insulator. The…
  mediumNumericalAsked the year before
- 2024 · Q47
  The following graph represents the T-V curves of an ideal gas (where T is the temperature and V the volume) at three pressures $P_1$ ,…
  mediumFigure-based
- 2022 · Q44
  The volume occupied by the molecules contained in 4.5 kg water at STP, if the intermolecular forces vanish away is :
  mediumNumerical
- 2020 · Q139
  A cylinder contains hydrogen gas at pressure of 249 kPa and temperature 27°C. Its density is : (R = 8.3 J mol $^{-1}$ K $^{-1}$ )
  easyNumericalNew idea
Repeated3 · 21%21%3/10
Repeated2 · 14%14%2/10
Repeated2 · 14%14%2/10
Repeated2 · 14%14%2/10

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

Ideas

Every idea inside this topic

5 different ideas were tested; 5 came more than once.

Ideal Gas Equation5×
numerical
Numerical · 11% next
Degrees of Freedom and Internal Energy3×
numerical
Numerical · 6% next
Mean Free Path2×
recall formula for mean free path
Numerical · 6% next
RMS Speed of Molecules2×
numerical
Numerical · 6% next
Molecular Kinetic Energy and Temperature2×
recall average energy per molecule of gas
One-line MCQ · 4% next

Idea	Times	Format	Chance next	Foundation for
Ideal Gas Equationnumerical	5	NumericalCalculation	11%	–
Degrees of Freedom and Internal Energynumerical	3	NumericalCalculation	6%	–
Mean Free Pathrecall formula for mean free path	2	NumericalCalculation	6%	–
RMS Speed of Moleculesnumerical	2	NumericalCalculation	6%	–
Molecular Kinetic Energy and Temperaturerecall average energy per molecule of gas	2	One-line MCQConcept	4%	–

Chance next is the historical rate at which an idea with this record came back in the following paper. It is low for every idea, which is why learning the topic beats memorising past questions. All repeated ideas

Every question

Kinetic Theory of Gases questions, year by year

The opening words of each question as it appeared in the official paper, with the idea it tested.

NEET 20262 questions

Q2
The mean free path of molecules in an ideal gas A is half that of another ideal gas B. The diameter of the spherical molecules of gas A is…
Idea: Mean Free Path
MediumNumerical
Q45
An ideal gas is made of polyatomic molecules. Each of the molecules has three translational, three rotational and f number of vibrational…
Idea: Degrees of Freedom and Internal Energy
MediumNumerical

NEET 20252 questions

Q14
An oxygen cylinder of volume 30 litre has 18.20 moles of oxygen. After some oxygen is withdrawn from the cylinder, its gauge pressure…
Idea: Ideal Gas Equation
Asked last yearMediumNumerical
Q29
A container has two chambers of volumes $V_1$ = 2 litres and $V_2$ = 3 litres separated by a partition made of a thermal insulator. The…
Idea: Ideal Gas Equation
Asked last yearMediumNumerical

NEET 20241 question

Q47
The following graph represents the T-V curves of an ideal gas (where T is the temperature and V the volume) at three pressures $P_1$ ,…
Idea: Ideal Gas Equation
MediumFigure-based · figure

NEET 20231 question

Q12
The temperature of a gas is −50° C. To what temperature the gas should be heated so that the rms speed is increased by 3 times?
Idea: RMS Speed of Molecules
MediumNumerical

NEET 20221 question

Q44
The volume occupied by the molecules contained in 4.5 kg water at STP, if the intermolecular forces vanish away is :
Idea: Ideal Gas Equation
MediumNumerical

NEET 20211 question

Q27
Match Column - I and Column - II and choose the correct match from the given choices. Column - I | Column - II (A) Root mean square speed…
Idea: Degrees of Freedom and Internal Energy
EasyMatch the lists

NEET 20203 questions

Q139
A cylinder contains hydrogen gas at pressure of 249 kPa and temperature 27°C. Its density is : (R = 8.3 J mol $^{-1}$ K $^{-1}$ )
Idea: Ideal Gas Equation
New ideaEasyNumerical
Q155
The mean free path for a gas, with molecular diameter d and number density n can be expressed as :
Idea: Mean Free Path
New ideaMediumOne-line MCQ
Q162
The average thermal energy for a mono-atomic gas is : ( $k_B$ is Boltzmann constant and T, absolute temperature)
Idea: Molecular Kinetic Energy and Temperature
Asked last yearEasyOne-line MCQ

NEET 20191 question

Q12
Increase in temperature of a gas filled in a container would lead to :
Idea: Molecular Kinetic Energy and Temperature
New ideaEasyOne-line MCQ

NEET 20181 question

Q3
At what temperature will the rms speed of oxygen molecules become just sufficient for escaping from the Earth's atmosphere ? (Given : Mass…
Idea: RMS Speed of Molecules
New ideaMediumNumerical

NEET 20171 question

Q2
A gas mixture consists of 2 moles of $\mathrm{O_2}$ and 4 moles of Ar at temperature T. Neglecting all vibrational modes, the total…
Idea: Degrees of Freedom and Internal Energy
EasyNumerical

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