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Sunday, 25 October

JEE Main · Chemistry · Class 11

Environmental Chemistry: JEE Main previous year questions

This chapter is not in NTA's JEE Main 2026 syllabus. It had 61 questions in the shifts Lumi analysed; they are kept here for reference.

Questions
61
in 60 of 108 shifts · 6 of 8 years
Average a shift
0.5
of 25 Chemistry · 0.0 since 2024 -0.7
Typical range
0.0–0.8
questions a shift; fewest 0.0, most 0.8
Syllabus
Dropped
NTA JEE Main 2026 syllabus
  • Typical range (fact)
  • Average a shift (fact)
  • Weighted estimate (model)

Questions are counted per shift, out of the 25 each subject has, in the shifts Lumi analysed; papers that offered 30 a subject (2017, 2021–2024) are scaled to 25. Typical range: the middle six of the eight years (2017, 2020–2026), leaving out the single highest and lowest year. The average and the range are historical fact. The weighted estimate is a model: each year's share, with recent years counting more (half-life three years), and chapters NTA dropped from the syllabus set near zero. It is a guide to effort, not a forecast of the paper.

Key findings

Environmental Chemistry at a glance

  1. 01

    50%

    of the 56 ideas in Lumi's map of the chapter have not been asked or touched on in the shifts analysed.

  2. 02

    0%

    of its questions asked for a numerical answer, 0.0 times the Chemistry average.

  3. 03

    0%

    of its questions were rated hard, against 6% across all Chemistry questions in the same shifts.

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.

0240.8’170.5’200.8’210.7’220.8’230’240’250’26

Raw count: 2017: 1 in 1 shift · 2020: 6 in 12 shifts · 2021: 22 in 24 shifts · 2022: 20 in 24 shifts · 2023: 11 in 12 shifts · 2024: 1 in 18 shifts · 2025: 0 in 8 shifts · 2026: 0 in 9 shifts.

Kind of question

SHARE OF QUESTIONS
  • Recall, single correct56%
  • Conceptual15%
  • Two statements15%
  • Match the list10%
  • Assertion–reason5%

Most common asks: definition recall (3); true statement selection on greenhouse gases (1); identify radical causing ozone depletion (1).

Profile

This chapter in numbers

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

Syllabus
Dropped
NTA JEE Main 2026
Last asked
2024
Share of Chemistry
1.8%
of its questions, all shifts analysed
Busiest year
2017
0.8 questions a shift
Year to year
Swings a lot
varies by about 0.3 questions a shift
Long-run direction
-0.10
questions a shift, per year
Easy questions
82%
0% rated hard
Numerical answer
0%
0.0× the Chemistry rate
With a figure
2%
graph, diagram or structure
Foundation for others
7%
of its ideas are used in other chapters

Difficulty, year by year

Each question rated easy, medium or hard. Each bar is that year’s split, so years compare directly; the number is the questions in that year’s analysed shifts (1 to 24 shifts a year).

  • 20171
  • 20206
  • 202122
  • 202220
  • 202311
  • 20241
  • 2025
  • 2026
  • Easy
  • Medium
  • Hard

What it asks you to do

SHARE OF QUESTIONS
  • Recall74%
  • Conceptual26%

Coverage

How much of the chapter JEE Main has used

We split the chapter into 56 ideas. In the 108 shifts analysed, JEE Main built a question around 19 of them. Most of the chapter has never been the main idea of a question, so past questions alone leave most of it out.

Asked as the main idea
19
Touched on in a question
9
Never asked
28

Topics

What repeats, topic by topic

This chapter's questions per topic in each year's analysed shifts. The number is the count; the shade is scaled to one shift, so a year with more analysed shifts (1 to 24 a year) does not look darker. 3 questions had no close topic in Lumi's map and count for the chapter only.

’17’20’21’22’23’24’25’26
022+questions in that year’s analysed shifts, shaded per shift

Drill down

Topic, idea, question

Open a topic to see every idea JEE Main tested inside it, then open an idea to read the questions. Each row shows its 8 years.

  • Open58 · 95%622199

    18 ideas inside

    • OpenRepeated7 · 12%33
    • OpenRepeated7 · 12%32
    • OpenRepeated6 · 10%22
    • OpenRepeated6 · 10%3
    • OpenRepeated5 · 9%3
    • OpenRepeated5 · 9%2
    • OpenRepeated3 · 5%
    • OpenRepeated3 · 5%
    • OpenRepeated2 · 3%
    • OpenRepeated2 · 3%
    • OpenRepeated2 · 3%
    • OpenRepeated2 · 3%
    • Open2 · 3%2
    • OpenRepeated2 · 3%
    • Open1 · 2%
    • Open1 · 2%
    • Open1 · 2%
    • Open1 · 2%
  • 10 Apr ’23 S2 · Q71
    The delicate balance of CO2\mathrm{CO_2} and O2\mathrm{O_2} is NOT disturbed by

    easySingle correct

  • 15 Apr ’23 S1 · Q68
    For a good quality cement, the ratio of silica to alumina is found to be

    easySingle correct

  • 26 Jul ’22 S2 · Q72
    Match **List I** with **List II**. List I (Pollutant) | List II (Source) A. Microorganisms | I. Strip mining B. Plant nutrients | II.…

    easyMatch the list

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

The exact ideas JEE Main has asked

Inside the topics, 18 different ideas were tested; 14 came more than once. These are the repeats, then the ideas new since 2024.

Dots are the 8 years with analysed shifts, 2017 to 2026.

Every question

All 61 Environmental Chemistry questions

Newest first, shift by shift. The newest 40 show their opening words; older ones name the idea they tested. Each opens with its options and the official answer.

JEE Main 20241 question

  1. 9 Apr 2024, Shift 1 · Q67The F−\mathrm{F^-} ions make the enamel on teeth much harder by converting hydroxyapatite (the enamel on the surface of teeth) into much…MediumSingle correct

JEE Main 202311 questions

  1. 6 Apr 2023, Shift 1 · Q71The possibility of photochemical smog formation is more atEasySingle correct
  2. 6 Apr 2023, Shift 2 · Q71The group of chemicals used as pesticide isEasySingle correct
  3. 8 Apr 2023, Shift 2 · Q70Which of these reactions is not a part of breakdown of ozone in stratosphere?MediumSingle correct
  4. 10 Apr 2023, Shift 1 · Q70Match List I with List II List I (Industry) List II (Waste Generated) (A) Steel plants (I) Gypsum (B) Thermal power plants (II) Fly ash…EasyMatch the list
  5. 10 Apr 2023, Shift 2 · Q71The delicate balance of CO2\mathrm{CO_2} and O2\mathrm{O_2} is NOT disturbed byEasySingle correct
  6. 11 Apr 2023, Shift 1 · Q71Given below are two statements: Statement I: If BOD is 4 ppm and dissolved oxygen is 8 ppm, then it is a good quality water. Statement II:…MediumTwo statements
  7. 12 Apr 2023, Shift 1 · Q73Match List I with List II LIST I / LIST II A. Nitrogen oxides in air - I. Eutrophication B. Methane in air - II. pH of rain water becomes…EasyMatch the list
  8. 13 Apr 2023, Shift 1 · Q72The radical which mainly causes ozone depletion in the presence of UV radiations is :EasySingle correct
  9. 13 Apr 2023, Shift 2 · Q71Which of the following are the Green house gases? A. Water vapour B. Ozone C. I2\mathrm{I_2} D. Molecular hydrogen Choose the most…EasyOther
  10. 15 Apr 2023, Shift 1 · Q68For a good quality cement, the ratio of silica to alumina is found to beEasySingle correct
  11. 15 Apr 2023, Shift 1 · Q71The possibility of photochemical smog formation will be minimum atEasySingle correct

JEE Main 202220 questions

  1. 25 Jul 2022, Shift 1 · Q72The photochemical smog does not generally contain :EasySingle correct
  2. 25 Jul 2022, Shift 2 · Q72Match List I with List II. List I | List II A. Sulphate | I. Pesticide B. Fluoride | II. Bending of bones C. Nicotine | III. Laxative…MediumMatch the list
  3. 26 Jul 2022, Shift 1 · Q70C˙l+CH4→A+B\dot{\mathrm{C}}\mathrm{l} + \mathrm{CH_4} \rightarrow \mathrm{A} + \mathrm{B} A and B in the above atmospheric reaction step are :EasySingle correct
  4. 26 Jul 2022, Shift 2 · Q72Match **List I** with **List II**. List I (Pollutant) | List II (Source) A. Microorganisms | I. Strip mining B. Plant nutrients | II.…EasyMatch the list
  5. 27 Jul 2022, Shift 1 · Q73Match List I with List II. List I (Pollutant) | List II (Disease/sickness) A. Sulphate (>500 ppm) | I. Methemoglobinemia B. Nitrate (>50…MediumMatch the list
  6. 27 Jul 2022, Shift 2 · Q71Given below are two statements : **Statement I :** The non bio-degradable fly ash and slag from steel industry can be used by cement…EasyTwo statements
  7. 28 Jul 2022, Shift 1 · Q71Given below are two statements : Statement I : In polluted water values of both dissolved oxygen and BOD are very low. Statement II :…EasyTwo statements
  8. 29 Jul 2022, Shift 2 · Q72Dinitrogen is a robust compound, but reacts at high altitudes to form oxides. The oxide of nitrogen that can damage plant leaves and…EasySingle correct
  9. 30 Jul 2022, Shift 2 · Q41Which of the following is not a component of photochemical smog?EasySingle correct
  10. 24 Jun 2022, Shift 2 · Q72Some gases are responsible for heating of atmosphere (green house effect). Identify from the following the gaseous species which does not…EasySingle correct
  11. 25 Jun 2022, Shift 1 · Q70The eutrophication of water body results in :EasySingle correct
  12. 25 Jun 2022, Shift 2 · Q72Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R. Assertion A: Polluted water may have…MediumAssertion–reason
  13. 26 Jun 2022, Shift 1 · Q72Polar stratospheric clouds facilitate the formation of :EasySingle correct
  14. 26 Jun 2022, Shift 2 · Q70The measured BOD values for four different water samples (A-D) are as follows: A = 3 ppm; B=18 ppm; C=21 ppm; D=4 ppm. The water samples…EasySingle correct
  15. 27 Jun 2022, Shift 1 · Q72Given below are two Statements : Statement I : Classical smog occurs in cool humid climate. It is a reducing mixture of smoke, fog and…EasyTwo statements
  16. 27 Jun 2022, Shift 2 · Q71On the surface of polar stratospheric clouds, hydrolysis of chlorine nitrate gives A and B while its reaction with HCl produces B and C.…MediumSingle correct
  17. 28 Jun 2022, Shift 1 · Q70Which amongst the following is not a pesticide ?EasySingle correct
  18. 28 Jun 2022, Shift 2 · Q72Correct statement about photo-chemical smog is :EasySingle correct
  19. 29 Jun 2022, Shift 1 · Q72The acid that is believed to be mainly responsible for the damage of Taj Mahal isEasySingle correct
  20. 29 Jun 2022, Shift 2 · Q72Sulphur dioxide is one of the components of polluted air. SO2\mathrm{SO_2} is also a major contributor to acid rain. The correct and…EasySingle correct

JEE Main 202122 questions

  1. 3 Aug 2021, Shift 1 · Q40Match List I with List II : List I : A. ‘Blue baby’ syndrome ; B. Eutrophication ; C. Minimata disease ; D. Itai-Itai disease List II : I.…EasyMatch the list
  2. 3 Aug 2021, Shift 2 · Q41Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A : Fluoride ion…EasyAssertion–reason
  3. 4 Aug 2021, Shift 1 · Q41In stratosphere, chlorofluorocarbon compounds break down by UV radiations, releasing 'X' free radical, which further causes ozone layer…EasySingle correct
  4. 4 Aug 2021, Shift 2 · Q40The INCORRECT statement among those given below regarding smog isEasySingle correct
  5. 26 Aug 2021, Shift 1 · Q40The conversion of hydroxyapatite occurs due to presence of F−\mathrm{F^-} ions in water. The correct formula of hydroxyapatite is :MediumSingle correct
  6. 26 Aug 2021, Shift 2 · Q41Given below are two statements : one is labelled as Assertion (A) and the other is labelled as Reason (R). Assertion (A) : Photochemical…EasyAssertion–reason
  7. 27 Aug 2021, Shift 1 · Q41The gas ‘A’ is having very low reactivity reaches to stratosphere. It is non-toxic and non-flammable but dissociated by UV-radiations in…EasySingle correctHas a figure
  8. 27 Aug 2021, Shift 2 · Q39In stratosphere most of the ozone formation is assisted by :EasySingle correct
  9. 31 Aug 2021, Shift 1 · Q41BOD Values for Clean vs Polluted Water · Easy · Single correct
  10. 31 Aug 2021, Shift 2 · Q40Acid Rain Mechanism · Easy · Single correct
  11. 24 Feb 2021, Shift 1 · Q39Greenhouse Effect · Easy · Single correct
  12. 24 Feb 2021, Shift 2 · Q41Water Quality BOD and COD · Easy · Two statements
  13. 25 Feb 2021, Shift 1 · Q41Classical vs Photochemical Smog · Medium · Two statements
  14. 25 Feb 2021, Shift 2 · Q40Acid Rain pH Threshold · Easy · Two statements
  15. 26 Feb 2021, Shift 1 · Q39Primary Reactions of Photochemical Smog · Easy · Single correct
  16. 22 Jul 2021, Shift 2 · Q41Eutrophication and Dissolved Oxygen Limits · Easy · Single correct
  17. 25 Jul 2021, Shift 2 · Q41Ozone Layer Depletion · Medium · Two statements
  18. 16 Mar 2021, Shift 2 · Q40Greenhouse Effect · Easy · Other
  19. 17 Mar 2021, Shift 1 · Q40Classical vs Photochemical Smog · Easy · Single correct
  20. 17 Mar 2021, Shift 2 · Q41Eutrophication and Dissolved Oxygen Limits · Easy · Other
  21. 18 Mar 2021, Shift 1 · Q41Greenhouse Effect · Medium · Other
  22. 18 Mar 2021, Shift 2 · Q41Eutrophication and Dissolved Oxygen Limits · Easy · Two statements

JEE Main 20206 questions

  1. 8 Jan 2020, Shift 1 · Q38Greenhouse Effect · Easy · Other
  2. 9 Jan 2020, Shift 2 · Q38Water Quality BOD and COD · Easy · Single correct
  3. 2 Sep 2020, Shift 1 · Q38Ozone Layer Depletion · Easy · Single correct
  4. 3 Sep 2020, Shift 1 · Q38Acid Rain Mechanism · Easy · Single correct
  5. 3 Sep 2020, Shift 2 · Q38Acid Rain Mechanism · Easy · Other
  6. 5 Sep 2020, Shift 1 · Q39Eutrophication and Dissolved Oxygen Limits · Easy · Single correct

JEE Main 20171 question

  1. 2 Apr 2017 (offline) · Q44Fluoride Limits in Drinking Water · Easy · Single correct

Questions from the official JEE Main papers published by NTA. Chapter, topic and idea tags, counts and notes are Lumi’s. Pattern: Asked most years.

More Chemistry, Class 11

All JEE Main chaptersJEE Main Chemistry analysisStudy plan