NEET UG · Chemistry · Class 11

Some Basic Concepts of Chemistry: NEET previous year questions

14 questions in ten years of NEET, asked in 9 of 10 years. Here is what this chapter tests and how.

Asked in 10 years: 14; 9 of 10 papers
10-year average: 1.3; a paper · 2.2 since 2024 +1.3
Typical range: 1–2; questions a paper; fewest 0, most 3
Weighted estimate: 1.8; model, recent papers count more · about 7 marks

Typical range (fact)
10-year average (fact)
Weighted estimate (model)

Typical range: questions per paper in the middle eight of the ten papers, leaving out the single highest and lowest year (about the 10th to 90th percentile), each paper scaled to 180 questions. The ten-year average and the range are historical fact. The weighted estimate is a model: each paper's share, with recent papers counting more (half-life three years), and dropped syllabus removed. It is a guide to effort, not a forecast.

What to do

How to spend time on Some Basic Concepts of Chemistry

Priority

Lower priority

Among the chapters that shared the last fifth of the questions. How bands are set

Past questions: 14in 9 of 10 papers
Study plan gives it: 11 hover 12 months; 9 h over 6

Study this chapter →Practise →

Ideas asked most often

Stoichiometric Calculations5×
Mole-Mass-Particle Conversions3×
Empirical and Molecular Formula2×

62 of the 73 ideas in Lumi’s map of this chapter have not been asked or touched in ten years. New questions often come from ideas like these, so learn the whole chapter, not just the list above.

Questions per year

Kind of question

SHARE OF 10 YEARS

Calculation86%
Recall7%
Application7%

Most common asks: numerical (8); compare number of molecules in samples (1); compare number of atoms in equal mass (1).

Profile

This chapter in numbers

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

Rank, all NEET chapters: #50; of 80 by weighted estimate
Rank in Chemistry: #14; of 21 chapters
Share of the paper: 0.8%; ten-year average
Busiest year: 2024; 3 questions
Year to year: Steady; varies by about 0.8 questions
Long-run direction: +0.16; questions per paper, per year
Easy questions: 71%; 25% of ideas rated hard
With a figure: 0%; graph, diagram or structure
Study time: 11 h; 9 h on a 6-month plan
Marks per study hour: 0.61; #26 of 80 chapters
Foundation for others: 28%; of its ideas are used in other chapters

Difficulty, year by year

Each question rated easy, medium or hard against NCERT.

2017
20182
20191
20201
20211
20221
20231
20243
20252
20262

Easy
Medium
Hard

What it asks you to do

SHARE OF QUESTIONS

Calculation71%
Multi-step14%
Application7%
Recall7%

Coverage

How much of the chapter NEET has used

We split the chapter into 73 ideas. In ten years NEET built a question around 6 of them. Most of the chapter has never been asked, which is why learning it whole beats memorising past questions.

Asked as the main idea: 6
Touched on in a question: 5
Never asked: 62

Topics

What repeats, topic by topic

Questions per topic in each year's paper. Topics that come every year are worth learning first.

Mole Concept · Every year14
211111322

’17’18’19’20’21’22’23’24’25’26

Topic	2017	’18	2019	’20	2021	’22	2023	’24	2025	’26	Total
Mole ConceptEvery year	·	2	1	1	1	1	1	3	2	2	14

03+questions in that year’s paper

Mole Concept
Expect a short numerical problem (one or two formula steps, four numeric options) about Mole Concept. Past framings centre on: numerical; compare number of molecules in samples.

Drill down

Topic, idea, question

Open a topic to see every idea NEET tested inside it, then open an idea to read the questions. Each row shows its ten papers.

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

Open14 · 100%100%9/102322
7 ideas inside
- Repeated5 · 36%36%5/10
- 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

The exact ideas NEET has asked

Inside the topics, 7 different ideas were tested. These came more than once, or are new since 2024.

Stoichiometric Calculations5×
numerical
Mole-Mass-Particle Conversions3×
compare number of molecules in samples
Empirical and Molecular Formula2×
numerical
Significant FiguresNew1×
round numbers to given decimal places
Laws of Chemical CombinationNew1×
identify law dalton's theory could not explain
Counting Atoms in Polyatomic MoleculesNew1×
select samples with equal number of atoms

Idea	Times	Usually asked as
Stoichiometric Calculationsnumerical	5	Numerical
Mole-Mass-Particle Conversionscompare number of molecules in samples	3	One-line MCQ
Empirical and Molecular Formulanumerical	2	Numerical
Significant Figuresround numbers to given decimal places	1	One-line MCQNew
Laws of Chemical Combinationidentify law dalton's theory could not explain	1	One-line MCQNew
Counting Atoms in Polyatomic Moleculesselect samples with equal number of atoms	1	OtherNew

Every question

Some Basic Concepts of Chemistry questions, year by year

The opening words of each question as it appeared in the official paper.

NEET 20262 questions

Q51The numbers 17.0145 and 21.0235 were rounded to three figures after the decimal point. The resulting numbers, respectively, areOne-line MCQ
Q63The 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)Numerical

NEET 20252 questions

Q54Dalton's Atomic theory could not explain which of the following?One-line MCQ
Q68Among 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)…Other

NEET 20243 questions

Q651 gram of sodium hydroxide was treated with 25 mL of 0.75 M HCl solution, the mass of sodium hydroxide left unreacted is equal toNumerical
Q78The highest number of helium atoms is inOne-line MCQ
Q92A 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 =…Numerical

NEET 20231 question

Q56The right option for the mass of CO $_2$ produced by heating 20 g of 20% pure limestone is (Atomic mass of Ca = 40)…Numerical

NEET 20221 question

Q76What 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 ?…Numerical

NEET 20211 question

Q58An organic compound contains 78% (by wt.) carbon and remaining percentage of hydrogen. The right option for the empirical formula of this…Numerical

NEET 20201 question

Q123Which one of the followings has maximum number of atoms ?Numerical

NEET 20191 question

Q68The number of moles of hydrogen molecules required to produce 20 moles of ammonia through Haber's process is :Numerical

NEET 20182 questions

Q57A 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…Numerical
Q78In which case is the number of molecules of water maximum ?One-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.

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