JEE Main · Chemistry · Some Basic Concepts of Chemistry
Mole Concept: JEE Main previous year questions
80 questions in the 108 JEE Main shifts Lumi analysed, in 8 of 8 years. Pattern: Asked most years. 23 came in 2024–26. Here is how it is asked and which ideas come back.
- Questions
- 80
- in 68 of 108 shifts
- Years asked
- 8/8
- last asked 2026
- Weighted estimate
- 0.7
- model; history: 0.7 a shift on average, typically 0.5–0.8
Key findings
- 01
Asked in 8 of 8 years with analysed shifts and in 68 of 108 shifts: 80 questions, #19 of 196 topics. It came in every year with analysed shifts.
- 02
27% of its questions since 2020 tested an idea no earlier year had asked; 36 repeated an idea from the year before.
- 03
The most repeated idea is Molarity Calculation, asked 16 times in 16 shifts (2020, 2021, 2022, 2023, 2024), most often as “molarity from mass percent and density”.
- 04
JEE Main has asked 18 of the 50 ideas in this topic; 26 have never been asked, directly or inside another question.
- 05
Mostly asked as numerical value (65%); 65% need a numerical answer, 61% are easy and 1% hard.
- 06
The skill tested most is calculation (88%), then multi-step (9%).
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: 10 in 12 shifts · 2021: 15 in 24 shifts · 2022: 23 in 24 shifts · 2023: 8 in 12 shifts · 2024: 12 in 18 shifts · 2025: 3 in 8 shifts · 2026: 8 in 9 shifts.
- Up to 2023
- 0.7
- a shift, of 25
- Since 2024
- 0.6
- -0.1
- Usual gap
- 1.3 yrs
- between years asking it
- Shifts with it
- 68/108
- 63% of analysed shifts
Recent framings
- match list on atoms in given masses
- statement I/II on mole fraction and Raoult deviation
- empirical formula from mass percentage
Revise first
- Mole and Avogadro Calculations · asked 2021, 2022, 2023, 2025, 2026
- Mole Fraction Calculation · asked 2020, 2024, 2026
- Empirical Formula from Mass Percentage · asked 2020, 2022, 2026
How it is asked
Difficulty, format and skill
Across all 80 questions on Mole Concept since 2017.
Difficulty
QUESTIONS- Easy49 · 61%
- Medium30 · 38%
- Hard1 · 1%
Format
SHARE- Numerical value · 52 Q65%
- Single correct · 22 Q28%
- Match the list · 2 Q3%
- Assertion–reason · 2 Q3%
- Other · 1 Q1%
- Two statements · 1 Q1%
Skill tested
SHARE- Calculation · 70 Q88%
- Multi-step · 7 Q9%
- Application · 1 Q1%
- Recall · 1 Q1%
- Conceptual · 1 Q1%
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 18 of the 50 ideas in this topic. 26 have never been asked yet.
- Asked directly18 · 36%
- Touched inside another question6 · 12%
- 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.
14 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
18 different ideas were tested; 12 came more than once.
molarity from mass percent and density
Numerical value · 16 shifts · 13 numericalorder of total atoms in given amounts
Numerical value · 10 shifts · 4 numericalmolality from ppm and molarity
Numerical value · 7 shifts · 6 numericalempirical formula from analysis data
Numerical value · 6 shifts · 3 numericalproduct moles from limiting reagent
Numerical value · 5 shifts · 6 numericalmoles and molecules from gas volume
Numerical value · 5 shifts · 3 numericalmole fraction from mass percent
Numerical value · 5 shifts · 2 numericalmolarity from molality and density
Numerical value · 5 shifts · 3 numericalvolume of acid to neutralize base
Numerical value · 5 shifts · 4 numericalmolarity after neutralisation and dilution
Numerical value · 3 shifts · 2 numericalmolality from percentage composition
Assertion–reason · 3 shifts · 1 numericalmolecular formula from percentage composition
Single correct · 2 shiftsmolarity from purity and specific gravity
Numerical value · 1 shift · 1 numericalminimum molar mass of protein from percentage
Numerical value · 1 shift · 1 numericalpercentage purity from gas evolved
Numerical value · 1 shift · 1 numericalpercentage strength of hydrogen peroxide solution
Numerical value · 1 shift · 1 numericalisotope ratio from average atomic mass
Single correct · 1 shiftwater of crystallisation from normality
Numerical value · 1 shift · 1 numerical
| Idea | Years asked | Times | Shifts | Format | Numerical |
|---|---|---|---|---|---|
| Molarity Calculationmolarity from mass percent and density | 16 | 16 | Numerical valueCalculation | 13 | |
| Mole and Avogadro Calculationsorder of total atoms in given amounts | 11 | 10 | Numerical valueCalculation | 4 | |
| PPM and Mass Percentagemolality from ppm and molarity | 7 | 7 | Numerical valueCalculation | 6 | |
| Empirical Formula from Mass Percentageempirical formula from analysis data | 6 | 6 | Numerical valueCalculation | 3 | |
| Limiting Reagent and Reaction Yieldproduct moles from limiting reagent | 6 | 5 | Numerical valueCalculation | 6 | |
| Molar Mass and Gas Volumemoles and molecules from gas volume | 5 | 5 | Numerical valueCalculation | 3 | |
| Mole Fraction Calculationmole fraction from mass percent | 5 | 5 | Numerical valueCalculation | 2 | |
| Molarity and Molality Interconversionmolarity from molality and density | 5 | 5 | Numerical valueCalculation | 3 | |
| Normality and n-factor Calculationvolume of acid to neutralize base | 5 | 5 | Numerical valueCalculation | 4 | |
| Molarity of Diluted and Mixed Solutionsmolarity after neutralisation and dilution | 3 | 3 | Numerical valueCalculation | 2 | |
| Molality Calculationmolality from percentage composition | 3 | 3 | Assertion–reasonCalculation | 1 | |
| Molecular Formula Determinationmolecular formula from percentage composition | 2 | 2 | Single correctCalculation | – | |
| Specific Gravity in Concentrationmolarity from purity and specific gravity | 1 | 1 | Numerical valueCalculation | 1 | |
| Minimum Molar Mass Calculationminimum molar mass of protein from percentage | 1 | 1 | Numerical valueCalculation | 1 | |
| Percentage Purity of Samplespercentage purity from gas evolved | 1 | 1 | Numerical valueCalculation | 1 | |
| Volume Strength of H2O2percentage strength of hydrogen peroxide solution | 1 | 1 | Numerical valueCalculation | 1 | |
| Average Atomic Mass from Isotopesisotope ratio from average atomic mass | 1 | 1 | Single correctCalculation | – | |
| Water of Crystallization Determinationwater of crystallisation from normality | 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
Mole Concept 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 20268 questions in 6 shifts
- 4 Apr, Shift 1Q51Number of moles and number of molecules in L of at STP respectively are
Idea: Molar Mass and Gas Volume
EasySingle correct - 4 Apr, Shift 1Q73g of a bromo hydrocarbon (X) was subjected to Carius analysis, gave g of AgBr. The percentage of carbon in the compound (X)…
Idea: Empirical Formula from Mass Percentage
MediumNumerical value - 4 Apr, Shift 2Q51The correct order of total number of atoms present in (A) 2 moles of cyclohexane (B) 684 g of sucrose (C) 90.8 L of dihydrogen at STP is:
Idea: Mole and Avogadro Calculations
Asked the year beforeEasySingle correct - 5 Apr, Shift 1Q54What is the mole fraction of water in 10% by weight (w/w) of aqueous urea solution? [Given: Molar mass of H, O, C and N are 1, 16, 12 and…
Idea: Mole Fraction Calculation
EasySingle correct - 6 Apr, Shift 1Q51An oxide of iron contains 69.9% iron, its empirical formula, is: (Given : Molar mass of Fe and O are 56 and 16 g mol respectively.)
Idea: Empirical Formula from Mass Percentage
EasySingle correct - 6 Apr, Shift 2Q51Which of the following contain the same number of atoms ? (Given : Molar mass in g mol of H, He, O and S are 1, 4, 16 and 32…
Idea: Mole and Avogadro Calculations
Asked the year beforeEasyOther - 8 Apr, Shift 2Q51Match List - I with List - II. List - I (Mass of substance) | List - II (Number of atoms) A. 1.8 mg water | I.…
Idea: Mole and Avogadro Calculations
Asked the year beforeEasyMatch the list - 8 Apr, Shift 2Q52Given below are two statements : Given : Molar mass of C, H, O, Cl are 12, 1, 16 and 35.5 g mol, respectively Statement I : In 30%…
Idea: Mole Fraction Calculation
MediumTwo statements
JEE Main 20253 questions in 3 shifts
- 3 Apr, Shift 1Q51Among g (each) of the following elements, which one will have the highest number of atoms? Element: Pb, Po, Pr and Pt
Idea: Mole and Avogadro Calculations
EasySingle correct - 3 Apr, Shift 2Q5410 mL of 2 M NaOH solution is added to 20 mL of 1 M HCl solution kept in a beaker. Now, 10 mL of this mixture is poured into a volumetric…
Idea: Molarity of Diluted and Mixed Solutions
MediumSingle correct - 4 Apr, Shift 2Q73Sea water, which can be considered as a 6 molar (6 M) solution of NaCl, has a density of . The concentration of…
Idea: PPM and Mass Percentage
Asked the year beforeMediumNumerical value
JEE Main 202412 questions in 11 shifts
- 4 Apr, Shift 1Q61The Molarity (M) of an aqueous solution containing 5.85 g of NaCl in 500 mL water is : (Given : Molar Mass Na : 23 and Cl : 35.5…
Idea: Molarity Calculation
Asked the year beforeEasySingle correct - 5 Apr, Shift 1Q73An organic compound has 42.1% carbon, 6.4% hydrogen and remainder is oxygen. If its molecular weight is 342, then its molecular formula is :
Idea: Molecular Formula Determination
Asked the year beforeMediumSingle correct - 6 Apr, Shift 1Q61The density of 'x' M solution ('x' molar) of NaOH is 1.12 g mL, while in molality, the concentration of the solution is 3 m (3…
Idea: Molarity and Molality Interconversion
EasySingle correct - 6 Apr, Shift 2Q61Molality () of 3 M aqueous solution of NaCl is : (Given : Density of solution , Molar mass in…
Idea: Molarity and Molality Interconversion
EasySingle correct - 8 Apr, Shift 2Q81A solution is prepared by adding 1 mole ethyl alcohol in 9 mole water. The mass percent of solute in the solution is ________ (Integer…
Idea: PPM and Mass Percentage
Asked the year beforeEasyNumerical value - 8 Apr, Shift 2Q85Molality of an aqueous solution of urea is 4.44 m. Mole fraction of urea in solution is . Value of is ________.…
Idea: Mole Fraction Calculation
MediumNumerical value - 9 Apr, Shift 1Q81Molarity (M) of an aqueous solution containing g of anhyd. in 500 mL solution at 32 C is M.…
Idea: Molarity and Molality Interconversion
MediumNumerical value - 1 Feb, Shift 1Q81Consider the following reaction : If 72 mmol of is…
Idea: Limiting Reagent and Reaction Yield
Asked the year beforeEasyNumerical value - 29 Jan, Shift 1Q81A solution of is 31.4% by mass and has a density of 1.25g/mL. The molarity of the …
Idea: Molarity Calculation
Asked the year beforeEasyNumerical value - 30 Jan, Shift 1Q81The mass of sodium acetate () required to prepare 250 mL of 0.35 M aqueous solution is ________ g. (Molar mass of…
Idea: Molarity Calculation
Asked the year beforeEasyNumerical value - 30 Jan, Shift 2Q61If a substance 'A' dissolves in solution of a mixture of 'B' and 'C' with their respective number of moles as ,…
Idea: Mole Fraction Calculation
EasySingle correct - 31 Jan, Shift 2Q83The molarity of 1 L orthophosphoric acid () having 70% purity by weight (specific gravity 1.54 g cm) is _________…
Idea: Specific Gravity in Concentration
New ideaEasyNumerical value
JEE Main 20238 questions in 7 shifts
- 6 Apr, Shift 1Q81If 5 moles of is mixed with 2 moles of , the maximum number of moles of …
Idea: Limiting Reagent and Reaction Yield
Asked the year beforeEasyNumerical value - 6 Apr, Shift 2Q61The volume of 0.02 M aqueous HBr required to neutralize 10.0 mL of 0.01 M aqueous is (Assume complete neutralization)
Idea: Normality and n-factor Calculation
Asked the year beforeEasySingle correct - 10 Apr, Shift 1Q61The number of molecules and moles in 2.8375 litres of at STP are respectively
Idea: Mole and Avogadro Calculations
Asked the year beforeEasySingle correct - 10 Apr, Shift 2Q61Match List I with List II LIST I A. 16 g of (g) B. 1 g of (g) C. 1 mole of (g) D. 0.5 mol of…
Idea: Mole and Avogadro Calculations
Asked the year beforeEasyMatch the list - 10 Apr, Shift 2Q80Given below are two statements: one is labelled as Assertion A and the other is labelled as Reason R Assertion A : 3.1500g of hydrated…
Idea: Molarity Calculation
Asked the year beforeEasyAssertion–reason - 11 Apr, Shift 1Q81A solution of sugar is obtained by mixing 200g of its 25% solution and 500g of its 40% solution (both by mass). The mass percentage of the…
Idea: PPM and Mass Percentage
Asked the year beforeEasyNumerical value - 11 Apr, Shift 2Q64A solution is prepared by adding 2 g of “X” to 1 mole of water. Mass percent of “X” in the solution is
Idea: PPM and Mass Percentage
Asked the year beforeEasySingle correct - 12 Apr, Shift 1Q61A metal chloride contains 55.0% of chlorine by weight . 100 mL vapours of the metal chloride at STP weigh 0.57 g. The molecular formula of…
Idea: Molecular Formula Determination
New ideaMediumSingle correct
JEE Main 202223 questions in 16 shifts
- 25 Jul, Shift 2Q88A sample of 4.5 mg of an unknown monohydric alcohol, R-OH was added to methylmagnesium iodide. A gas is evolved and is collected and its…
Idea: Molar Mass and Gas Volume
MediumNumerical value - 26 Jul, Shift 1Q81Chlorophyll extracted from the crushed green leaves was dissolved in water to make 2 L solution of Mg of concentration 48 ppm. The number…
Idea: PPM and Mass Percentage
MediumNumerical value - 26 Jul, Shift 1Q85When 800 mL of 0.5 M nitric acid is heated in a beaker, its volume is reduced to half and 11.5 g of nitric acid is evaporated. The…
Idea: Molarity Calculation
Asked the year beforeMediumNumerical value - 26 Jul, Shift 2Q61Hemoglobin contains 0.34% of iron by mass. The number of Fe atoms in 3.3 g of hemoglobin is (Given: Atomic mass of Fe is 56 u,…
Idea: Mole and Avogadro Calculations
Asked the year beforeEasySingle correct - 27 Jul, Shift 1Q61250 g solution of D-glucose in water contains 10.8% of carbon by weight. The molality of the solution is nearest to (Given: Atomic Weights…
Idea: Molality Calculation
Asked the year beforeMediumSingle correct - 27 Jul, Shift 2Q81The normality of in the solution obtained on mixing 100 mL of 0.1 M with 50 mL of 0.1 M NaOH is…
Idea: Normality and n-factor Calculation
Asked the year beforeMediumNumerical value - 28 Jul, Shift 1Q81In the given reaction, if one mole of each of X and Y with 0.05 mol of Z gives compound…
Idea: Limiting Reagent and Reaction Yield
MediumNumerical value - 28 Jul, Shift 2Q512L of 0.2M is reacted with 2L of 0.1M NaOH solution, the molarity of the resulting product in the…
Idea: Molarity of Diluted and Mixed Solutions
New ideaEasyNumerical value - 30 Jul, Shift 2Q51The density of 4 molal solution of NaOH is 1.160 g . The molarity of the solution is ________ M. (Given : Molar mass of…
Idea: Molarity and Molality Interconversion
Asked the year beforeMediumNumerical value - 24 Jun, Shift 2 · Q61Empirical Formula from Mass PercentageEasy
- 25 Jun, Shift 1 · Q81Mole and Avogadro CalculationsAsked the year beforeEasy
- 25 Jun, Shift 1 · Q85Molarity of Diluted and Mixed SolutionsNew ideaMedium
- 25 Jun, Shift 1 · Q90Mole and Avogadro CalculationsAsked the year beforeEasy
- 25 Jun, Shift 2 · Q81Minimum Molar Mass CalculationNew ideaEasy
- 25 Jun, Shift 2 · Q90Normality and n-factor CalculationAsked the year beforeEasy
- 26 Jun, Shift 1 · Q61Molarity CalculationAsked the year beforeEasy
- 26 Jun, Shift 2 · Q81Limiting Reagent and Reaction YieldMedium
- 26 Jun, Shift 2 · Q90Limiting Reagent and Reaction YieldEasy
- 27 Jun, Shift 1 · Q61Molality CalculationAsked the year beforeEasy
- 27 Jun, Shift 1 · Q89Molar Mass and Gas VolumeMedium
- 27 Jun, Shift 2 · Q81Empirical Formula from Mass PercentageMedium
- 28 Jun, Shift 2 · Q61Empirical Formula from Mass PercentageMedium
- 28 Jun, Shift 2 · Q81Molar Mass and Gas VolumeMedium
JEE Main 202115 questions in 15 shifts
- 3 Aug, Shift 1 · Q60Volume Strength of H2O2New ideaEasy
- 3 Aug, Shift 2 · Q51Percentage Purity of SamplesNew ideaMedium
- 4 Aug, Shift 1 · Q51Molarity CalculationAsked the year beforeEasy
- 26 Aug, Shift 1 · Q51Molarity and Molality InterconversionNew ideaMedium
- 26 Aug, Shift 2 · Q51Molarity CalculationAsked the year beforeMedium
- 31 Aug, Shift 1 · Q51Molarity CalculationAsked the year beforeEasy
- 31 Aug, Shift 2 · Q51Molarity CalculationAsked the year beforeEasy
- 24 Feb, Shift 1 · Q51Molarity CalculationAsked the year beforeEasy
- 25 Feb, Shift 2 · Q51Normality and n-factor CalculationAsked the year beforeMedium
- 26 Feb, Shift 2 · Q51Molarity CalculationAsked the year beforeMedium
- 22 Jul, Shift 2 · Q51Molarity CalculationAsked the year beforeEasy
- 17 Mar, Shift 1 · Q51Molality CalculationNew ideaMedium
- 17 Mar, Shift 2 · Q51Mole and Avogadro CalculationsNew ideaEasy
- 18 Mar, Shift 1 · Q51Mole and Avogadro CalculationsNew ideaEasy
- 18 Mar, Shift 2 · Q51Molarity CalculationAsked the year beforeEasy
JEE Main 202010 questions in 9 shifts
- 8 Jan, Shift 1 · Q46PPM and Mass PercentageNew ideaMedium
- 9 Jan, Shift 1 · Q46Molarity CalculationNew ideaEasy
- 9 Jan, Shift 2 · Q47PPM and Mass PercentageNew ideaEasy
- 2 Sep, Shift 2 · Q50Empirical Formula from Mass PercentageNew ideaHard
- 3 Sep, Shift 1 · Q46Mole Fraction CalculationNew ideaEasy
- 3 Sep, Shift 2 · Q46Molarity CalculationNew ideaEasy
- 3 Sep, Shift 2 · Q49Normality and n-factor CalculationNew ideaMedium
- 4 Sep, Shift 1 · Q46Limiting Reagent and Reaction YieldNew ideaEasy
- 4 Sep, Shift 2 · Q46Water of Crystallization DeterminationNew ideaMedium
- 6 Sep, Shift 2 · Q40Average Atomic Mass from IsotopesNew ideaEasy
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.