JEE Main · Chemistry · Redox Reactions
Redox Reactions: JEE Main previous year questions
50 questions in the 108 JEE Main shifts Lumi analysed, in 7 of 8 years. Pattern: Asked most years. 15 came in 2024–26. Here is how it is asked and which ideas come back.
- Questions
- 50
- in 41 of 108 shifts
- Years asked
- 7/8
- last asked 2026
- Weighted estimate
- 0.4
- model; history: 0.4 a shift on average, typically 0.3–0.8
Key findings
- 01
Asked in 7 of 8 years with analysed shifts and in 41 of 108 shifts: 50 questions, #61 of 196 topics. The years that asked it were 1.5 apart on average.
- 02
41% of its questions since 2020 tested an idea no earlier year had asked; 19 repeated an idea from the year before.
- 03
The most repeated idea is Oxidation Number Assignment, asked 9 times in 9 shifts (2021, 2022, 2023, 2024), most often as “oxidation state in complex salt”.
- 04
JEE Main has asked 16 of the 50 ideas in this topic; 26 have never been asked, directly or inside another question.
- 05
Mostly asked as numerical value (54%); 54% need a numerical answer, 38% are easy and 2% hard. It went down from 0.5 to 0.3 questions a shift since 2024.
- 06
The skill tested most is calculation (48%), then conceptual (22%).
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: 1 in 1 shift · 2020: 4 in 12 shifts · 2021: 10 in 24 shifts · 2022: 9 in 24 shifts · 2023: 11 in 12 shifts · 2024: 12 in 18 shifts · 2025: 0 in 8 shifts · 2026: 3 in 9 shifts.
- Up to 2023
- 0.5
- a shift, of 25
- Since 2024
- 0.3
- -0.2
- Usual gap
- 1.5 yrs
- between years asking it
- Shifts with it
- 41/108
- 38% of analysed shifts
How it is asked
Difficulty, format and skill
Across all 50 questions on Redox Reactions since 2017.
Difficulty
QUESTIONS- Easy19 · 38%
- Medium30 · 60%
- Hard1 · 2%
Format
SHARE- Numerical value · 27 Q54%
- Single correct · 17 Q34%
- Two statements · 2 Q4%
- Other · 2 Q4%
- Match the list · 1 Q2%
- Assertion–reason · 1 Q2%
Skill tested
SHARE- Calculation · 24 Q48%
- Conceptual · 11 Q22%
- Application · 8 Q16%
- Multi-step · 4 Q8%
- Recall · 3 Q6%
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 16 of the 50 ideas in this topic. 26 have never been asked yet.
- Asked directly16 · 32%
- Touched inside another question8 · 16%
- Never asked26 · 52%
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.
13 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
16 different ideas were tested; 10 came more than once.
oxidation state in complex salt
Numerical value · 9 shifts · 5 numericalbalance disproportionation reaction
Single correct · 7 shiftsmolarity from redox titration
Numerical value · 6 shifts · 5 numericalmedium for permanganate reaction from oxidation state change
Numerical value · 6 shifts · 4 numericalh+ required in permanganate oxalate reaction
Numerical value · 4 shifts · 2 numericalidentify set of species reducing dichromate
Single correct · 3 shiftsmolarity from redox titration
Numerical value · 3 shifts · 3 numericalconcentration from iodometric titration
Numerical value · 2 shifts · 2 numericaljustify dual behaviour from reactions
Numerical value · 2 shifts · 1 numericalsum of coefficients on balancing redox equations
Numerical value · 2 shifts · 2 numericalcoefficient in balanced redox equation
Numerical value · 1 shift · 1 numericalcount species undergoing disproportionation
Numerical value · 1 shift · 1 numericalcovalency and oxidation state of central atom
Single correct · 1 shiftassertion-reason on low oxidation state complexes
Assertion–reason · 1 shiftbalance sulfur disproportionation in base
Numerical value · 1 shift · 1 numericalidentify redox reaction among xenon compounds
Single correct · 1 shift
| Idea | Years asked | Times | Shifts | Format | Numerical |
|---|---|---|---|---|---|
| Oxidation Number Assignmentoxidation state in complex salt | 9 | 9 | Numerical valueCalculation | 5 | |
| Disproportionation Balancingbalance disproportionation reaction | 7 | 7 | Single correctConceptual | – | |
| Law of Chemical Equivalence in Redoxmolarity from redox titration | 6 | 6 | Numerical valueCalculation | 5 | |
| Permanganate n-Factor Across Mediamedium for permanganate reaction from oxidation state change | 6 | 6 | Numerical valueCalculation | 4 | |
| Ion-Electron Acidich+ required in permanganate oxalate reaction | 4 | 4 | Numerical valueCalculation | 2 | |
| Identifying Redox Agentsidentify set of species reducing dichromate | 3 | 3 | Single correctConceptual | – | |
| Mohr's Salt Redox Titrationsmolarity from redox titration | 3 | 3 | Numerical valueCalculation | 3 | |
| Iodometric Titration Reactionsconcentration from iodometric titration | 2 | 2 | Numerical valueCalculation | 2 | |
| Thiosulfate-Iodine Reaction Stoichiometryjustify dual behaviour from reactions | 2 | 2 | Numerical valueConceptual | 1 | |
| Oxidation State Methodsum of coefficients on balancing redox equations | 2 | 2 | Numerical valueCalculation | 2 | |
| Balancing in Neutral/Faintly Alkaline Mediacoefficient in balanced redox equation | 1 | 1 | Numerical valueCalculation | 1 | |
| Predicting Redox Feasibility via Extreme Statescount species undergoing disproportionation | 1 | 1 | Numerical valueApplication | 1 | |
| Oxidation Number via Coordinate Bondscovalency and oxidation state of central atom | 1 | 1 | Single correctApplication | – | |
| Oxidation States in Metal Carbonylsassertion-reason on low oxidation state complexes | 1 | 1 | Assertion–reasonConceptual | – | |
| Ion-Electron Basicbalance sulfur disproportionation in base | 1 | 1 | Numerical valueCalculation | 1 | |
| Identifying Non-Redox Reactionsidentify redox reaction among xenon compounds | 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
Redox Reactions questions, year by year
The newest 40 show their opening words as they appeared in the official paper; older ones name the idea they tested. Open one for its options and the official answer.
JEE Main 20263 questions in 3 shifts
- 2 Apr, Shift 1Q61Which of the following sets includes all the species that will change the orange colour of in acidic medium ?
Idea: Identifying Redox Agents
MediumSingle correct - 4 Apr, Shift 1Q56In order to oxidise a mixture of mole each of , , and…
Idea: Law of Chemical Equivalence in Redox
MediumSingle correct - 6 Apr, Shift 2Q73500 mL of 0.2 M solution in basic medium when mixed with 500 mL of 1.5 M KI solution, oxidises iodide ions to liberate…
Idea: Iodometric Titration Reactions
MediumNumerical value
JEE Main 202412 questions in 10 shifts
- 4 Apr, Shift 1Q87Only 2 mL of solution of unknown molarity is required to reach the end point of a titration of 20 mL of oxalic acid (2…
Idea: Law of Chemical Equivalence in Redox
MediumNumerical value - 6 Apr, Shift 2Q64Match List - I with List - II. List - I (Reaction) (A) (B)…
Idea: Disproportionation Balancing
EasyMatch the list - 8 Apr, Shift 1Q64Thiosulphate reacts differently with iodine and bromine in the reactions given below:…
Idea: Thiosulfate-Iodine Reaction Stoichiometry
MediumSingle correct - 9 Apr, Shift 1Q65Given below are two statements : Statement (I) : The oxidation state of an element in a particular compound is the charge acquired by its…
Idea: Oxidation Number Assignment
Asked the year beforeMediumTwo statements - 1 Feb, Shift 1Q67In acidic medium, shows oxidising action as represented in the half reaction :…
Idea: Ion-Electron Acidic
Asked the year beforeEasySingle correct - 1 Feb, Shift 1Q68Which of the following reactions are disproportionation reactions ? (A) (B)…
Idea: Disproportionation Balancing
MediumOther - 27 Jan, Shift 1Q85From the given list, the number of compounds with +4 oxidation state of Sulphur is __________.…
Idea: Oxidation Number Assignment
Asked the year beforeEasyNumerical value - 29 Jan, Shift 1Q63Chlorine undergoes disproportionation in alkaline medium as shown below :…
Idea: Disproportionation Balancing
EasySingle correct - 30 Jan, Shift 1Q85If the above equation is balanced with integer…
Idea: Balancing in Neutral/Faintly Alkaline Media
New ideaMediumNumerical value - 30 Jan, Shift 2Q84Total number of species from the following which can undergo disproportionation reaction is ________.…
Idea: Predicting Redox Feasibility via Extreme States
New ideaMediumNumerical value - 31 Jan, Shift 2Q65Given below are two statements : Statement I : solid undergoes disproportionation reaction under alkaline conditions to…
Idea: Disproportionation Balancing
MediumTwo statements - 31 Jan, Shift 2Q86Number of moles of ions required by 1 mole of to oxidise oxalate ion to is ________.
Idea: Ion-Electron Acidic
Asked the year beforeMediumNumerical value
JEE Main 202311 questions in 7 shifts
- 6 Apr, Shift 1Q65Which of the following options are correct for the reaction…
Idea: Identifying Redox Agents
MediumOther - 6 Apr, Shift 1Q90In ammonium – phosphomolybdate, the oxidation state of Mo is + ________
Idea: Oxidation Number Assignment
Asked the year beforeMediumNumerical value - 6 Apr, Shift 2Q69During the reaction of permanganate with thiosulphate, the change in oxidation of manganese occurs by value of 3. Identify which of the…
Idea: Permanganate n-Factor Across Media
Asked the year beforeMediumSingle correct - 6 Apr, Shift 2Q70Given below are two statements: one is labelled as "Assertion A" and the other is labelled as "Reason R" Assertion A: In the complex…
Idea: Oxidation States in Metal Carbonyls
New ideaMediumAssertion–reason - 8 Apr, Shift 1Q61What is the value of ?
Idea: Ion-Electron Acidic
New ideaEasySingle correct - 10 Apr, Shift 2Q90In alkaline medium, the reduction of permanganate anion involves a gain of ____________ electrons.
Idea: Permanganate n-Factor Across Media
Asked the year beforeEasyNumerical value - 13 Apr, Shift 1Q81is titrated with ferrous ammonium sulphate hexahydrate in presence of dilute . Number of water…
Idea: Permanganate n-Factor Across Media
Asked the year beforeEasyNumerical value - 13 Apr, Shift 2Q64The covalency and oxidation state respectively of boron in , are
Idea: Oxidation Number via Coordinate Bonds
New ideaMediumSingle correct - 13 Apr, Shift 2Q88See the following chemical reaction:…
Idea: Ion-Electron Acidic
New ideaEasyNumerical value - 15 Apr, Shift 1Q88The total change in the oxidation state of manganese involved in the reaction of and potassium iodide in the acidic…
Idea: Permanganate n-Factor Across Media
Asked the year beforeEasyNumerical value - 15 Apr, Shift 1Q90In Chromyl chloride, the oxidation state of chromium is (+) __________.
Idea: Oxidation Number Assignment
Asked the year beforeEasyNumerical value
JEE Main 20229 questions in 7 shifts
- 26 Jul, Shift 1Q68Which of the given reactions is not an example of disproportionation reaction ?
Idea: Disproportionation Balancing
Asked the year beforeEasySingle correct - 26 Jul, Shift 1Q69The dark purple colour of disappears in the titration with oxalic acid in acidic medium. The overall change in the…
Idea: Permanganate n-Factor Across Media
Asked the year beforeEasySingle correct - 26 Jul, Shift 2Q8520 mL of 0.02 M hypo solution is used for the titration of 10 mL of copper sulphate solution, in the presence of excess of KI using starch…
Idea: Iodometric Titration Reactions
New ideaMediumNumerical value - 27 Jul, Shift 1Q8120 mL of 0.02 M solution is used for the titration of 10 mL of solution in the acidic medium. The…
Idea: Law of Chemical Equivalence in Redox
Asked the year beforeEasyNumerical value - 27 Jul, Shift 1Q88In the titration of and oxalic acid in acidic medium, the change in oxidation number of carbon at the end point is _____
Idea: Oxidation Number Assignment
Asked the year beforeEasyNumerical value - 24 Jun, Shift 1Q86The difference in oxidation state of chromium in chromate and dichromate salts is ______.
Idea: Oxidation Number Assignment
Asked the year beforeEasyNumerical value - 26 Jun, Shift 2Q68Which one of the following is an example of disproportionation reaction ?
Idea: Disproportionation Balancing
Asked the year beforeMediumSingle correct - 28 Jun, Shift 1Q81A 2.0 g sample containing is treated with HCl liberating . The gas is passed into a…
Idea: Thiosulfate-Iodine Reaction Stoichiometry
New ideaMediumNumerical value - 28 Jun, Shift 2Q900.01 M solution was added to 20.0 mL of 0.05 M Mohr’s salt solution through a burette. The initial reading of 50 mL…
Idea: Mohr's Salt Redox Titrations
Asked the year beforeMediumNumerical value
JEE Main 202110 questions in 9 shifts
- 27 Aug, Shift 1Q39In polythionic acid, ( = 3 to 5) the oxidation state(s) of sulphur is/are :
Idea: Oxidation Number Assignment
New ideaMediumSingle correct - 27 Aug, Shift 1Q55When 10 mL of an aqueous solution of was titrated in acidic medium, equal volume of 0.1 M of an aqueous solution of…
Idea: Mohr's Salt Redox Titrations
New ideaMediumNumerical value - 31 Aug, Shift 2Q38In which one of the following sets all species show disproportionation reaction ?
Idea: Disproportionation Balancing
New ideaMediumSingle correct - 24 Feb, Shift 1Q57The reaction of sulphur in alkaline medium is given below :…
Idea: Ion-Electron Basic
New ideaMediumNumerical value - 25 Feb, Shift 1Q55In basic medium oxidises to form and itself changes into…
Idea: Law of Chemical Equivalence in Redox
Asked the year beforeMediumNumerical value - 26 Feb, Shift 2 · Q59Permanganate n-Factor Across MediaNew ideaHard
- 25 Jul, Shift 1 · Q51Mohr's Salt Redox TitrationsNew ideaMedium
- 25 Jul, Shift 2 · Q32Oxidation Number AssignmentNew ideaEasy
- 17 Mar, Shift 1 · Q57Law of Chemical Equivalence in RedoxAsked the year beforeMedium
- 18 Mar, Shift 2 · Q38Oxidation Number AssignmentNew ideaEasy
JEE Main 20204 questions in 4 shifts
- 9 Jan, Shift 1 · Q35Identifying Redox AgentsNew ideaEasy
- 2 Sep, Shift 2 · Q49Oxidation State MethodNew ideaEasy
- 4 Sep, Shift 1 · Q49Law of Chemical Equivalence in RedoxNew ideaMedium
- 4 Sep, Shift 2 · Q49Oxidation State MethodNew ideaMedium
JEE Main 20171 question in 1 shift
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.
More topics in Redox Reactions
This is the only topic tagged in this chapter.