JEE Main · Chemistry · States of Matter
Real Gases: JEE Main previous year questions
7 questions in the 108 JEE Main shifts Lumi analysed, in 4 of 8 years. Pattern: Comes in cycles. 1 came in 2024–26. Here is how it is asked and which ideas come back.
- Questions
- 7
- in 7 of 108 shifts
- Years asked
- 4/8
- last asked 2024
- Weighted estimate
- 0.0
- model; history: 0.0 a shift on average, typically 0.0–0.1
Key findings
- 01
Asked in 4 of 8 years with analysed shifts and in 7 of 108 shifts: 7 questions, #185 of 196 topics. Last asked in 2024.
- 02
71% of its questions since 2020 tested an idea no earlier year had asked; 1 repeated an idea from the year before.
- 03
The most repeated idea is Units of VdW Constants, asked 2 times in 2 shifts (2021, 2024), most often as “dimension of physical quantity from formula”.
- 04
JEE Main has asked 5 of the 51 ideas in this topic; 44 have never been asked, directly or inside another question.
- 05
Mostly asked as single correct (43%); 43% need a numerical answer, 43% are easy and 0% hard.
- 06
The skill tested most is calculation (43%), then application (29%).
Questions a shift, year by year
Out of the 25 Chemistry questions in a shift. Years differ in how many shifts Lumi analysed, so each year is scaled to one shift.
Raw count: 2017: 0 in 1 shift · 2020: 0 in 12 shifts · 2021: 2 in 24 shifts · 2022: 2 in 24 shifts · 2023: 2 in 12 shifts · 2024: 1 in 18 shifts · 2025: 0 in 8 shifts · 2026: 0 in 9 shifts.
- Up to 2023
- 0.1
- a shift, of 25
- Since 2024
- 0.0
- 0.0
- Usual gap
- 1.0 yrs
- between years asking it
- Shifts with it
- 7/108
- 6% of analysed shifts
How it is asked
Difficulty, format and skill
Across all 7 questions on Real Gases since 2017.
Difficulty
QUESTIONS- Easy3 · 43%
- Medium4 · 57%
- Hard0 · 0%
Format
SHARE- Single correct · 3 Q43%
- Numerical value · 3 Q43%
- Other · 1 Q14%
Skill tested
SHARE- Calculation · 3 Q43%
- Application · 2 Q29%
- Conceptual · 2 Q29%
Repeats
New idea, or one asked before?
Each column is a year. Blue questions tested an idea no earlier year had asked; navy ones went back to an idea from an earlier year. 2017 is the first year, so everything in it counts as new. Heights are question counts, and Lumi analysed 1 to 24 shifts a year, so compare the split inside a column rather than heights across years.
- Idea asked for the first time
- Idea asked in an earlier year
Coverage of the topic
JEE Main has asked 5 of the 51 ideas in this topic. 44 have never been asked yet.
- Asked directly5 · 10%
- Touched inside another question2 · 4%
- Never asked44 · 86%
Ideas come from Lumi’s JEE syllabus map. A never-asked idea is not a safe skip: across all of JEE Main, 22% of questions since 2024 tested an idea no earlier year had asked.
Drill down
Chapter, idea, question
Every idea JEE Main tested in this topic, with its eight years. Open one to read the questions.
5 ideas inside
Squares are the 8 years with analysed shifts, 2017 to 2026. A number is the questions that year when there is more than one; the shade is scaled to one shift, so a year with more analysed shifts (1 to 24 a year) does not look darker. Share is of the level above.
Ideas
Every idea inside this topic
5 different ideas were tested; 2 came more than once.
dimension of physical quantity from formula
Single correct · 2 shiftsvolume from compressibility factor
Numerical value · 2 shifts · 2 numericalorder/ranking of van der waals constant a
Other · 1 shiftconditions of greatest deviation from ideal gas
Single correct · 1 shiftderivative of compressibility factor for gas equation
Numerical value · 1 shift · 1 numerical
| Idea | Years asked | Times | Shifts | Format | Numerical |
|---|---|---|---|---|---|
| Units of VdW Constantsdimension of physical quantity from formula | 2 | 2 | Single correctApplication | – | |
| Compressibility Factor Zvolume from compressibility factor | 2 | 2 | Numerical valueCalculation | 2 | |
| Predicting 'a' from Molecular Structureorder/ranking of van der waals constant a | 1 | 1 | OtherApplication | – | |
| Gas Liquefactionconditions of greatest deviation from ideal gas | 1 | 1 | Single correctConceptual | – | |
| High Pressure VdW Limitderivative of compressibility factor for gas equation | 1 | 1 | Numerical valueCalculation | 1 |
Times and shifts count every analysed shift. Across JEE Main, 78% of questions since 2024 went back to an idea an earlier year had asked; the rest were new. All repeated ideas
Every question
Real Gases questions, year by year
The opening words of each question as it appeared in the official paper, with the idea it tested. Open one for its options and the official answer.
JEE Main 20241 question in 1 shift
- 5 Apr, Shift 2Q31What is the dimensional formula of in the equation , where letters have their usual meaning.
Idea: Units of VdW Constants
MediumSingle correct
JEE Main 20232 questions in 2 shifts
- 8 Apr, Shift 2Q62Arrange the following gases in increasing order of van der Waals constant 'a' A. Ar B. C. D.…
Idea: Predicting 'a' from Molecular Structure
New ideaEasyOther - 13 Apr, Shift 1Q82A certain quantity of real gas occupies a volume of at 100 atm and 500 K when its compressibility factor is 1.07.…
Idea: Compressibility Factor Z
Asked the year beforeMediumNumerical value
JEE Main 20222 questions in 2 shifts
- 27 Jul, Shift 2Q82For a real gas at 25°C temperature and high pressure (99 bar) the value of compressibility factor is 2, so the value of Vander Waal’s…
Idea: Compressibility Factor Z
New ideaMediumNumerical value - 30 Jul, Shift 2Q31Combination of temperature and pressure causing the greatest deviation from ideal gas behaviour is;
Idea: Gas Liquefaction
New ideaEasySingle correct
JEE Main 20212 questions in 2 shifts
- 27 Aug, Shift 1Q31The unit of the van der Waals gas equation parameter ‘a’ in…
Idea: Units of VdW Constants
New ideaEasySingle correct - 26 Feb, Shift 1Q52A certain gas obeys . The value of is . The value…
Idea: High Pressure VdW Limit
New ideaMediumNumerical value
Questions from the official JEE Main Paper 1 shifts published by NTA (CBSE for 2017). Questions NTA dropped are left out. Topic and idea tags, counts and notes are Lumi’s.