JEE Main · Chemistry · Surface Chemistry

Adsorption: JEE Main previous year questions

Name: Adsorption: JEE Main previous year questions
Creator: Lumi

31 questions in the 108 JEE Main shifts Lumi analysed, in 5 of 8 years. Pattern: Asked most years. 3 came in 2024–26. Here is how it is asked and which ideas come back.

Questions: 31; in 29 of 108 shifts
Years asked: 5/8; last asked 2024
Chance in a shift: 9%; calibrated model, how we compute it
Weighted estimate: 0.0; model; history: 0.2 a shift on average, typically 0.0–0.3

Key findings

01
Asked in 5 of 8 years with analysed shifts and in 29 of 108 shifts: 31 questions, #106 of 196 topics. Last asked in 2024.
02
52% of its questions since 2020 tested an idea no earlier year had asked; 12 repeated an idea from the year before.
03
The most repeated idea is Freundlich Logarithmic Plot, asked 7 times in 7 shifts (2020, 2021, 2022, 2023), most often as “adsorption from freundlich log plot”.
04
JEE Main has asked 13 of the 50 ideas in this topic; 34 have never been asked, directly or inside another question.
05
Mostly asked as single correct (29%); 29% need a numerical answer, 35% are easy and 0% hard. It went down from 0.3 to 0.1 questions a shift since 2024.
06
The skill tested most is conceptual (29%), then recall (23%).

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: 3 in 12 shifts · 2021: 9 in 24 shifts · 2022: 9 in 24 shifts · 2023: 7 in 12 shifts · 2024: 3 in 18 shifts · 2025: 0 in 8 shifts · 2026: 0 in 9 shifts.

Up to 2023: 0.3; a shift, of 25
Since 2024: 0.1; -0.2
Usual gap: 1.0 yrs; between years asking it
Shifts with it: 29/108; 27% of analysed shifts

How it is asked

Difficulty, format and skill

Across all 31 questions on Adsorption since 2017.

Difficulty

QUESTIONS

1120

Easy11 · 35%
Medium20 · 65%
Hard0 · 0%

Format

Single correct · 9 Q29%
Numerical value · 9 Q29%
Diagram based · 5 Q16%
Other · 4 Q13%
Assertion–reason · 2 Q6%
Match the list · 1 Q3%
Two statements · 1 Q3%

Skill tested

Conceptual · 9 Q29%
Recall · 7 Q23%
Data or graph · 7 Q23%
Calculation · 7 Q23%
Diagram reading · 1 Q3%

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.

’17’20’21’22’23’24’25’26

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

Coverage of the topic

JEE Main has asked 13 of the 50 ideas in this topic. 34 have never been asked yet.

1334

Asked directly13 · 26%
Touched inside another question3 · 6%
Never asked34 · 68%

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.

chapterAskedShareYears’17’20’21’22’23’24’25’26

Open21 · 68%68%4/83864
9 ideas inside
- OpenRepeated7 · 33%33%4/8222
- OpenRepeated3 · 14%14%2/82
- OpenRepeated2 · 10%10%2/8
- Open2 · 10%10%1/82
- OpenRepeated2 · 10%10%2/8
- OpenRepeated2 · 10%10%2/8
- Open1 · 5%5%1/8
- Open1 · 5%5%1/8
- Open1 · 5%5%1/8
Open7 · 23%23%3/8223
Open3 · 10%10%3/8

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

13 different ideas were tested; 10 came more than once.

Freundlich Logarithmic Plot7×
adsorption from freundlich log plot
Numerical value · 7 shifts · 5 numerical
Adsorption Chromatography Principle3×
identify technique using a principle
Single correct · 3 shifts
Adsorption in Froth Flotation3×
identify role of reagent in froth flotation
Single correct · 3 shifts
Critical Temperature and Extent of Adsorption3×
adsorption order from critical temperatures
Single correct · 3 shifts
Adsorption in Chromatography2×
adsorbents used in adsorption chromatography
Other · 2 shifts
Adsorption Chromatography Principle2×
order of elution from tlc plate
Diagram based · 2 shifts · 1 numerical
Adsorption Theory of Heterogeneous Catalysis2×
count correct statements on heterogeneous catalysis theory
Match the list · 2 shifts · 1 numerical
Thermodynamics of Adsorption2×
sign of enthalpy for adsorption and micelle formation
Single correct · 2 shifts
Limits of Freundlich Exponent (1/n)2×
count correct statements on freundlich isotherm
Diagram based · 2 shifts
Freundlich Isotherm Equation2×
freundlich isotherm adsorbed volume
Numerical value · 2 shifts · 1 numerical
Adsorption from Solutions1×
mass adsorbed per gram from solution
Numerical value · 1 shift · 1 numerical
Factors Affecting Adsorption1×
adsorption isotherm at two temperatures
Diagram based · 1 shift
Physisorption vs Chemisorption1×
valid statements on adsorption
Other · 1 shift

Idea	Times	Shifts	Format	Numerical
Freundlich Logarithmic Plotadsorption from freundlich log plot	7	7	Numerical valueCalculation	5
Adsorption Chromatography Principleidentify technique using a principle	3	3	Single correctConceptual	–
Adsorption in Froth Flotationidentify role of reagent in froth flotation	3	3	Single correctRecall	–
Critical Temperature and Extent of Adsorptionadsorption order from critical temperatures	3	3	Single correctConceptual	–
Adsorption in Chromatographyadsorbents used in adsorption chromatography	2	2	OtherDiagram reading	–
Adsorption Chromatography Principleorder of elution from tlc plate	2	2	Diagram basedCalculation	1
Adsorption Theory of Heterogeneous Catalysiscount correct statements on heterogeneous catalysis theory	2	2	Match the listConceptual	1
Thermodynamics of Adsorptionsign of enthalpy for adsorption and micelle formation	2	2	Single correctConceptual	–
Limits of Freundlich Exponent (1/n)count correct statements on freundlich isotherm	2	2	Diagram basedConceptual	–
Freundlich Isotherm Equationfreundlich isotherm adsorbed volume	2	2	Numerical valueCalculation	1
Adsorption from Solutionsmass adsorbed per gram from solution	1	1	Numerical valueCalculation	1
Factors Affecting Adsorptionadsorption isotherm at two temperatures	1	1	Diagram basedData or graph	–
Physisorption vs Chemisorptionvalid statements on adsorption	1	1	OtherConceptual	–

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

Adsorption 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.

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.

Key findings

Questions a shift, year by year

Difficulty, format and skill

Difficulty

Format

Skill tested

New idea, or one asked before?

Coverage of the topic

Chapter, idea, question

Every idea inside this topic

Adsorption questions, year by year

JEE Main 20243 questions in 3 shifts

JEE Main 20237 questions in 6 shifts

JEE Main 20229 questions in 8 shifts

JEE Main 20219 questions in 9 shifts

JEE Main 20203 questions in 3 shifts

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