JEE Main · Chemistry · Haloalkanes and Haloarenes
Stereoisomerism: JEE Main previous year questions
25 questions in the 108 JEE Main shifts Lumi analysed, in 7 of 8 years. Pattern: Asked most years. 10 came in 2024–26. Here is how it is asked and which ideas come back.
- Questions
- 25
- in 24 of 108 shifts
- Years asked
- 7/8
- last asked 2026
- Weighted estimate
- 0.2
- model; history: 0.2 a shift on average, typically 0.1–0.4
Key findings
- 01
Asked in 7 of 8 years with analysed shifts and in 24 of 108 shifts: 25 questions, #127 of 196 topics.
- 02
68% of its questions since 2020 tested an idea no earlier year had asked; 4 repeated an idea from the year before.
- 03
The most repeated idea is Chiral Centers, asked 12 times in 12 shifts (2020, 2022, 2023, 2024, 2026), most often as “relationship between two wedge-dash structures”.
- 04
JEE Main has asked 11 of the 47 ideas in this topic; 30 have never been asked, directly or inside another question.
- 05
Mostly asked as numerical value (56%); 56% need a numerical answer, 28% are easy and 24% hard.
- 06
The skill tested most is multi-step (28%), then application (20%).
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: 5 in 12 shifts · 2021: 4 in 24 shifts · 2022: 5 in 24 shifts · 2023: 1 in 12 shifts · 2024: 8 in 18 shifts · 2025: 1 in 8 shifts · 2026: 1 in 9 shifts.
- Up to 2023
- 0.2
- a shift, of 25
- Since 2024
- 0.2
- 0.0
- Usual gap
- 1.0 yrs
- between years asking it
- Shifts with it
- 24/108
- 22% of analysed shifts
How it is asked
Difficulty, format and skill
Across all 25 questions on Stereoisomerism since 2017.
Difficulty
QUESTIONS- Easy7 · 28%
- Medium12 · 48%
- Hard6 · 24%
Format
SHARE- Numerical value · 14 Q56%
- Single correct · 5 Q20%
- Diagram based · 2 Q8%
- Two statements · 2 Q8%
- Assertion–reason · 2 Q8%
Skill tested
SHARE- Multi-step · 7 Q28%
- Application · 5 Q20%
- Conceptual · 5 Q20%
- Diagram reading · 4 Q16%
- Calculation · 3 Q12%
- Recall · 1 Q4%
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 11 of the 47 ideas in this topic. 30 have never been asked yet.
- Asked directly11 · 23%
- Touched inside another question6 · 13%
- Never asked30 · 64%
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
11 different ideas were tested; 4 came more than once.
relationship between two wedge-dash structures
Numerical value · 12 shifts · 8 numericalstatement i/ii on cis/trans polarity and boiling point
Single correct · 2 shiftscount optically active chlorination products
Numerical value · 2 shifts · 2 numericalidentify structure from iupac name
Diagram based · 2 shiftscount geometrical isomers of polyene
Numerical value · 1 shift · 1 numericalcount stereoisomers of structure
Single correct · 1 shiftcis trans dipole moment assertion reason
Assertion–reason · 1 shiftstereoisomers of disubstituted cycloalkane
Numerical value · 1 shift · 1 numericaloptical purity from rotation
Numerical value · 1 shift · 1 numericalcount compounds showing geometrical isomerism
Numerical value · 1 shift · 1 numericalnumber of stereoisomers of 1,2-dimethylcyclopropane
Single correct · 1 shift
| Idea | Years asked | Times | Shifts | Format | Numerical |
|---|---|---|---|---|---|
| Chiral Centersrelationship between two wedge-dash structures | 12 | 12 | Numerical valueMulti-step | 8 | |
| Physical Properties of Geometrical Isomersstatement i/ii on cis/trans polarity and boiling point | 2 | 2 | Single correctConceptual | – | |
| Counting Optical Isomerscount optically active chlorination products | 2 | 2 | Numerical valueMulti-step | 2 | |
| Geometrical Isomerismidentify structure from iupac name | 2 | 2 | Diagram basedApplication | – | |
| Calculating Geometrical Isomers in Polyenescount geometrical isomers of polyene | 1 | 1 | Numerical valueMulti-step | 1 | |
| Calculating Total Stereoisomerscount stereoisomers of structure | 1 | 1 | Single correctMulti-step | – | |
| Physical Properties of Cis/Trans Isomerscis trans dipole moment assertion reason | 1 | 1 | Assertion–reasonConceptual | – | |
| Chirality in Substituted Cycloalkanesstereoisomers of disubstituted cycloalkane | 1 | 1 | Numerical valueApplication | 1 | |
| Enantiomeric Excess and Specific Rotationoptical purity from rotation | 1 | 1 | Numerical valueCalculation | 1 | |
| Counting Geometrical Isomerscount compounds showing geometrical isomerism | 1 | 1 | Numerical valueDiagram reading | 1 | |
| Geometrical Isomerism in Cycloalkanesnumber of stereoisomers of 1,2-dimethylcyclopropane | 1 | 1 | Single correctApplication | – |
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
Stereoisomerism 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 20261 question in 1 shift
- 4 Apr, Shift 2Q65The following structures are [figure: stereocentre C with Br (up), CH3 (hashed, left), Me (down), Cl (wedge, right)] and [figure:…
Idea: Chiral Centers
EasyDiagram based · figure
JEE Main 20251 question in 1 shift
- 7 Apr, Shift 2Q65Given below are two statements : Statement (I) : [figure: cis-1,2-dichloroethene] is more polar than [figure: cis-1,2-dibromoethene].…
Idea: Physical Properties of Geometrical Isomers
Asked the year beforeMediumTwo statements · figure
JEE Main 20248 questions in 7 shifts
- 5 Apr, Shift 1Q76Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : Cis form of…
Idea: Physical Properties of Cis/Trans Isomers
New ideaEasyAssertion–reason - 6 Apr, Shift 2Q75The incorrect statement regarding the geometrical isomers of 2-butene is :
Idea: Physical Properties of Geometrical Isomers
New ideaEasySingle correct - 8 Apr, Shift 1Q88The number of optical isomers in following compound is:__________ [figure: three fused cyclohexane rings in a linear (anthracene-type)…
Idea: Counting Optical Isomers
New ideaHardNumerical value · figure - 8 Apr, Shift 2Q89Total number of optically active compounds from the following is ___________. (1) Fischer projection: on top; H-C-OH;…
Idea: Chiral Centers
Asked the year beforeMediumNumerical value · figure - 9 Apr, Shift 2Q76Total number of stereo isomers possible for the given structure :
Idea: Calculating Total Stereoisomers
New ideaMediumSingle correct · figure - 1 Feb, Shift 1Q89Number of optical isomers possible for 2-chlorobutane ________.
Idea: Chiral Centers
Asked the year beforeEasyNumerical value - 30 Jan, Shift 2Q87Number. of geometrical isomers possible for the given structure is/are ________.
Idea: Calculating Geometrical Isomers in Polyenes
New ideaMediumNumerical value · figure - 30 Jan, Shift 2Q882-chlorobutane + (isomers) Total number of optically active isomers shown by…
Idea: Counting Optical Isomers
New ideaHardNumerical value
JEE Main 20231 question in 1 shift
- 11 Apr, Shift 2Q79Given below are two statements, one is labelled as Assertion A and the other is labelled as Reason R. Assertion A : A solution of the…
Idea: Chiral Centers
Asked the year beforeMediumAssertion–reason
JEE Main 20225 questions in 5 shifts
- 27 Jul, Shift 1Q89Optical activity of an enantiomeric mixture is and the specific rotation of (+) isomer is . The optical purity is…
Idea: Enantiomeric Excess and Specific Rotation
New ideaEasyNumerical value - 29 Jul, Shift 2Q75Given below are two statements. Statement I: The compound [figure: compound (A), a drawn structure with a stereocentre bearing…
Idea: Chiral Centers
MediumTwo statements · figure - 27 Jun, Shift 1Q90Total number of possible stereoisomers of dimethyl cyclopentane is __________.
Idea: Chirality in Substituted Cycloalkanes
New ideaHardNumerical value - 29 Jun, Shift 1Q89Observe structures of the following compounds [figure: five structures] The total number of structures/compounds which possess asymmetric…
Idea: Chiral Centers
EasyNumerical value · figure - 29 Jun, Shift 2Q88The number of chiral alcohol(s) with molecular formula is _____.
Idea: Chiral Centers
MediumNumerical value
JEE Main 20214 questions in 4 shifts
- 3 Aug, Shift 2Q44The correct structure of –2,4-dimethylhept-3-ene is,
Idea: Geometrical Isomerism
New ideaMediumDiagram based · figure - 4 Aug, Shift 1Q59From the following compounds, the total number of compound(s) which will show Geometrical isomerism is ________.
Idea: Counting Geometrical Isomers
New ideaHardNumerical value · figure - 26 Aug, Shift 2Q43The number of stereoisomers possible for 1,2-dimethyl cyclopropane is :
Idea: Geometrical Isomerism in Cycloalkanes
New ideaMediumSingle correct - 22 Jul, Shift 2Q44Which one of the following molecules does not show stereo isomerism ?
Idea: Geometrical Isomerism
New ideaMediumSingle correct
JEE Main 20205 questions in 5 shifts
- 8 Jan, Shift 1Q50The number of chiral centres in penicillin is ______.
Idea: Chiral Centers
New ideaMediumNumerical value - 2 Sep, Shift 1Q50The number of chiral carbons present in the molecule given below is ______.
Idea: Chiral Centers
New ideaMediumNumerical value · figure - 3 Sep, Shift 1Q41Which of the following compounds produces an optically inactive compound on hydrogenation ?
Idea: Chiral Centers
New ideaHardSingle correct · figure - 4 Sep, Shift 1Q50The number of chiral centres present in [B] is __________.
Idea: Chiral Centers
New ideaHardNumerical value · figure - 4 Sep, Shift 2Q50The number of chiral centres present in threonine is __________.
Idea: Chiral Centers
New ideaEasyNumerical 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.