NEET UG · Chemistry · Some Basic Concepts of Chemistry

Mole Concept: NEET previous year questions

14 questions in ten years of NEET, in 9 of 10 papers. Pattern: Every year. Here is how it is asked and which ideas come back.

Asked in 10 years: 14; about 1.3 per paper
Years asked: 9/10; last asked 2026
Chance of a question next paper: 84%; historical rate, how we compute it
Weighted estimate: 1.6; model; history: 1.3 a paper on average, typically 1–2

Key findings

01
Asked in 9 of 10 papers, 14 questions in all: #40 of 204 topics by ten-year total.
02
50% of its questions since 2018 tested an idea never asked before; 1 repeated an idea from the year before.
03
The most repeated idea is Stoichiometric Calculations, asked 5 times (2018, 2019, 2022, 2024, 2026), usually as “numerical”.
04
NEET has asked 6 of the 73 ideas in this topic; 62 have never been asked, directly or indirectly.
05
Mostly asked as numerical (64%); 71% easy, 7% hard, and up from 1.0 to 2.2 questions a paper since 2024.

Questions per year

Up to 2023: 1.0; per paper
Since 2024: 2.2; +1.3
Usual gap: 1.0 yrs; between papers asking it
Swing: ±0.8; questions, year to year

Recent framings

round numbers to given decimal places
numerical: mass of product from combustion
identify law Dalton's theory could not explain

Revise first

Stoichiometric Calculations (2018 2019 2022 2024 2026); Significant Figures (2026); Mole-Mass-Particle Conversions (2018 2020 2024)

How it is asked

Difficulty, format and skill

Across all 14 questions on Mole Concept since 2017.

Difficulty

QUESTIONS

103

Easy10 · 71%
Medium3 · 21%
Hard1 · 7%

Format

Numerical · 9 Q64%
One-line MCQ · 4 Q29%
Other · 1 Q7%

Skill tested

Calculation · 10 Q71%
Multi-step · 2 Q14%
Application · 1 Q7%
Recall · 1 Q7%

Repeats

New idea, or one asked before?

Each column is a paper. Blue questions tested an idea NEET had not asked before; navy ones went back to an idea from an earlier paper. 2017 is the first paper, so everything in it counts as new.

’17’18’19’20’21’22’23’24’25’26

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

Coverage of the topic

NEET has asked 6 of the 73 ideas in this topic. 62 have never been asked yet.

Asked directly6 · 8%
Touched inside another question5 · 7%
Never asked62 · 85%

Ideas come from Lumi’s syllabus map of NCERT. A never-asked idea is not a safe skip: most new questions come from exactly these.

Drill down

Idea, year, question

Every idea NEET tested in this topic, with its ten papers. Open one to read the questions.

ideaAskedShareYears’17’18’19’20’21’22’23’24’25’26

Repeated5 · 36%36%5/10
- 2026 · Q63
  The amount of carbon dioxide evolved upon complete combustion of 116 g of n-butane is (Given: atomic mass in amu H = 1, C = 12 and O = 16)
  easyNumerical
- 2024 · Q65
  1 gram of sodium hydroxide was treated with 25 mL of 0.75 M HCl solution, the mass of sodium hydroxide left unreacted is equal to
  easyNumerical
- 2022 · Q76
  What mass of 95% pure $\mathrm{CaCO_3}$ will be required to neutralise 50 mL of 0.5 M HCl solution according to the following reaction ?…
  mediumNumerical
- 2019 · Q68
  The number of moles of hydrogen molecules required to produce 20 moles of ammonia through Haber's process is :
  easyNumericalAsked the year before
- 2018 · Q57
  A mixture of 2.3 g formic acid and 4.5 g oxalic acid is treated with conc. $\mathrm{H_2SO_4}$ . The evolved gaseous mixture is passed…
  hardNumericalNew idea
Repeated3 · 21%21%3/10
Repeated2 · 14%14%2/10
1 · 7%7%1/10
1 · 7%7%1/10
1 · 7%7%1/10
1 · 7%7%1/10

Squares are the ten papers, 2017 to 2026; darker means more questions. Share is of the level above.

Ideas

Every idea inside this topic

7 different ideas were tested; 3 came more than once. Mole-Mass-Particle Conversions is the foundation for 59 other ideas in the syllabus.

Stoichiometric Calculations5×
numerical
Numerical · 11% next · foundation for 18
Mole-Mass-Particle Conversions3×
compare number of molecules in samples
One-line MCQ · 6% next · foundation for 59
Empirical and Molecular Formula2×
numerical
Numerical · 6% next · foundation for 2
Significant Figures1×
round numbers to given decimal places
One-line MCQ · 6% next
Counting Atoms in Polyatomic Molecules1×
select samples with equal number of atoms
Other · 6% next
Laws of Chemical Combination1×
identify law dalton's theory could not explain
One-line MCQ · 6% next · foundation for 6
Percentage Purity of a Sample1×
numerical
Numerical · 4% next

Idea	Times	Format	Chance next	Foundation for
Stoichiometric Calculationsnumerical	5	NumericalCalculation	11%	18 ideas
Mole-Mass-Particle Conversionscompare number of molecules in samples	3	One-line MCQCalculation	6%	59 ideas
Empirical and Molecular Formulanumerical	2	NumericalCalculation	6%	2 ideas
Significant Figuresround numbers to given decimal places	1	One-line MCQApplication	6%	–
Counting Atoms in Polyatomic Moleculesselect samples with equal number of atoms	1	OtherCalculation	6%	–
Laws of Chemical Combinationidentify law dalton's theory could not explain	1	One-line MCQRecall	6%	6 ideas
Percentage Purity of a Samplenumerical	1	NumericalCalculation	4%	–

Chance next is the historical rate at which an idea with this record came back in the following paper. It is low for every idea, which is why learning the topic beats memorising past questions. All repeated ideas

Every question

Mole Concept questions, year by year

The opening words of each question as it appeared in the official paper, with the idea it tested.

NEET 20262 questions

Q51
The numbers 17.0145 and 21.0235 were rounded to three figures after the decimal point. The resulting numbers, respectively, are
Idea: Significant Figures
New ideaEasyOne-line MCQ
Q63
The amount of carbon dioxide evolved upon complete combustion of 116 g of n-butane is (Given: atomic mass in amu H = 1, C = 12 and O = 16)
Idea: Stoichiometric Calculations
EasyNumerical

NEET 20252 questions

Q54
Dalton's Atomic theory could not explain which of the following?
Idea: Laws of Chemical Combination
New ideaEasyOne-line MCQ
Q68
Among the following, choose the ones with equal number of atoms. A. 212 g of $Na_2CO_3$ (s) [molar mass = 106 g] B. 248 g of $Na_2O$ (s)…
Idea: Counting Atoms in Polyatomic Molecules
New ideaMediumOther

NEET 20243 questions

Q65
1 gram of sodium hydroxide was treated with 25 mL of 0.75 M HCl solution, the mass of sodium hydroxide left unreacted is equal to
Idea: Stoichiometric Calculations
EasyNumerical
Q78
The highest number of helium atoms is in
Idea: Mole-Mass-Particle Conversions
EasyOne-line MCQ
Q92
A compound X contains 32% of A, 20% of B and remaining percentage of C. Then, the empirical formula of X is : (Given atomic masses of A =…
Idea: Empirical and Molecular Formula
MediumNumerical

NEET 20231 question

Q56
The right option for the mass of CO $_2$ produced by heating 20 g of 20% pure limestone is (Atomic mass of Ca = 40)…
Idea: Percentage Purity of a Sample
New ideaEasyNumerical

NEET 20221 question

Q76
What mass of 95% pure $\mathrm{CaCO_3}$ will be required to neutralise 50 mL of 0.5 M HCl solution according to the following reaction ?…
Idea: Stoichiometric Calculations
MediumNumerical

NEET 20211 question

Q58
An organic compound contains 78% (by wt.) carbon and remaining percentage of hydrogen. The right option for the empirical formula of this…
Idea: Empirical and Molecular Formula
New ideaEasyNumerical

NEET 20201 question

Q123
Which one of the followings has maximum number of atoms ?
Idea: Mole-Mass-Particle Conversions
EasyNumerical

NEET 20191 question

Q68
The number of moles of hydrogen molecules required to produce 20 moles of ammonia through Haber's process is :
Idea: Stoichiometric Calculations
Asked last yearEasyNumerical

NEET 20182 questions

Q57
A mixture of 2.3 g formic acid and 4.5 g oxalic acid is treated with conc. $\mathrm{H_2SO_4}$ . The evolved gaseous mixture is passed…
Idea: Stoichiometric Calculations
New ideaHardNumerical
Q78
In which case is the number of molecules of water maximum ?
Idea: Mole-Mass-Particle Conversions
New ideaEasyOne-line MCQ

Questions from the official NEET UG papers published by NTA (CBSE before 2019). Topic and idea tags, counts and notes are Lumi’s.