Some Basic Concepts of Chemistry- NEET Previous Year Questions with Solutions and Weightage

The chapter Some Basic Concepts of Chemistry lays the foundation for understanding advanced concepts in NEET Chemistry, it holds a 4% weightage in the NEET UG exam. This typically translates to about 2-3 questions from this chapter in the Chemistry section.. It introduces fundamental principles, including the structure of matter, atomic mass, molecular mass, mole concept, stoichiometry, and laws of chemical combination. This chapter is crucial for building a strong base for both physical and organic chemistry.

In NEET UG, this chapter serves as a stepping stone for solving numerical problems related to chemical reactions, molecular calculations, and conversions. Since NEET UG tests conceptual understanding and numerical accuracy, mastering this chapter is essential for achieving a high score.

While the weightage may appear moderate, the concepts covered in this chapter, such as the mole concept, stoichiometry, and laws of chemical combination, form the foundation for understanding many other topics in chemistry. Thus, mastering this chapter is important for building a strong base for the entire Chemistry syllabus.

Related Articles:

• Download NEET UG LAST 10 YEARS PYQS
• Download NEET UG 2024 Question Paper PDF with solutions and answer key for code- Q, R, S and T

Most important questions from Some Basic Concepts of Chemistry in NEET UG Chemistry with detailed solutions are given below.

NEET Chemistry Questions

Question 1:

A compound X contains 32% of A, 20% of B, and the remaining percentage of C. Then, the empirical formula of X is:

(Given atomic masses of A=64; B=40; C=32 u) [NEET 2024]

1. A₂BC₂
2. ABC₃
3. AB₂C₂
4. ABC₄

View Solution

Question 2:

1.0 g of H₂ has the same number of molecules as in: [NEET 2024]

1. 14 g of N₂
2. 18 g of H₂O
3. 16 g of CO
4. 28 g of N₂

View Solution

Question 3:

What mass of 95% pure CaCO₃ will be required to neutralize 50 mL of 0.5 M HCl solution according to the following reaction?

CaCO₃(s) + 2HCl(aq) → CaCl₂(aq) + CO₂(g) + 2H₂O(l)

[Calculate up to the second place of decimal point] [NEET 2022]

1. 1.25 g
2. 1.32 g
3. 3.65 g
4. 9.50 g

View Solution

Question 4:

Which one of the following has the maximum number of atoms? [NEET 2020]

1. 1g of Ag(s) [Atomic mass of Ag = 108]
2. 1g of Mg(s) [Atomic mass of Mg = 24]
3. 1g of O₂(g) [Atomic mass of O = 16]
4. 1g of Li(s) [Atomic mass of Li = 7]

View Solution

Question 5:

The density of 2 M aqueous solution of NaOH is 1.28 g/cm³. The molality of the solution is [Given that molecular mass of NaOH = 40 g mol⁻¹] [NEET 2019]

1. 1.20 m
2. 1.56 m
3. 1.67 m
4. 1.32 m

View Solution

Question 6:

The number of moles of hydrogen molecules required to produce 20 moles of ammonia through Haber's process is [NEET 2019]

1. 10
2. 20
3. 30
4. 40

View Solution

Question 7:

In which case is the number of molecules of water maximum? [NEET 2018]

1. 10⁻³ mol of water
2. 18 mL of water
3. 0.00224 L of water vapors at 1 atm and 273 K
4. 0.18 g of water

View Solution

Question 8:

A mixture of 2.3g formic acid and 4.5g oxalic acid is treated with conc. H₂SO₄. The evolved gaseous mixture is passed through KOH pellets. Weight (in g) of the remaining product at STP will be [NEET 2018]

1. 4.4
2. 1.4
3. 2.8
4. 3

View Solution

Question 9:

Which of the following is dependent on temperature? [NEET 2017]

1. Molality
2. Molarity
3. Mole fraction
4. Weight percentage

View Solution

Question 10:

The bond dissociation energies of X₂, Y₂, and XY are in the ratio of 1 : 0.5 : 1. ΔH for the formation of XY is –200 kJ mol⁻¹. The bond dissociation energy of X₂ will be [NEET 2018]

1. 200 kJ mol⁻¹
2. 800 kJ mol⁻¹
3. 100 kJ mol⁻¹
4. 400 kJ mol⁻¹

View Solution

Question 11:

The correct order of the stoichiometries of AgCl formed when AgNO₃ in excess is treated with the complexes: CoCl₃·6NH₃, CoCl₃·5NH₃, CoCl₃·4NH₃ respectively is [NEET 2017]

1. 1 AgCl, 3 AgCl, 2 AgCl
2. 3 AgCl, 1 AgCl, 2 AgCl
3. 3 AgCl, 2 AgCl, 1 AgCl
4. 2 AgCl, 3 AgCl, 1 AgCl

View Solution

Question 12:

Suppose the elements X and Y combine to form two compounds XY₂ and X₃Y₂. When 0.1 mole of XY₂ weighs 10g and 0.05 mole of X₃Y₂ weighs 9g, the atomic weights of X and Y are [NEET 2016]

1. 40, 30
2. 60, 40
3. 20, 30
4. 30, 20

View Solution

Question 13:

What is the mass of the precipitate formed when 50 mL of 16.9% solution of AgNO₃ is mixed with 50 mL of 5.8% NaCl solution? (Ag = 107.8, N = 14, O = 16, Na = 23, Cl = 35.5) [NEET 2015]

1. 7 g
2. 14 g
3. 28 g
4. 3.5 g

View Solution

Question 14:

A mixture of gases contains H₂ and O₂ gases in the ratio of 1:4 (w/w). What is the molar ratio of the two gases in the mixture? [NEET 2015]

1. 16:1
2. 2:1
3. 1:4
4. 4:1

View Solution

Question 15:

Equal masses of H₂, O₂, and methane have been taken in a container of volume V at temperature 27°C in identical conditions. The ratio of the volumes of gases H₂:O₂:methane would be: [NEET 2014]

1. 16:8:1
2. 16:1:2
3. 8:1:2
4. 8:16:1

View Solution

Question 16:

When 22.4 litres of H₂(g) is mixed with 11.2 litres of Cl₂(g), each at S.T.P., the moles of HCl (g) formed is equal to: [NEET 2014]

1. 2 mol of HCl (g)
2. 0.5 mol of HCl (g)
3. 1.5 mol of HCl (g)
4. 1 mol of HCl (g)

View Solution

Question 17:

In the Kjeldahl's method for estimation of nitrogen present in a soil sample, ammonia evolved from 0.75 gm of sample neutralized 10 mL of 1 M H₂SO₄. The percentage of nitrogen in the soil is: [NEET 2014]

1. 45.33
2. 35.33
3. 43.33
4. 37.33

View Solution

Question 18:

An excess of AgNO₃ is added to 100 mL of a 0.01 M solution of dichlorotetraaquachromium(III) chloride. The number of moles of AgCl precipitated would be [NEET 2013]

1. 0.001
2. 0.002
3. 0.003
4. 0.01

View Solution

Question 19:

What volume of oxygen gas (O₂) measured at 0°C and 1 atm, is needed to burn completely 1L of propane gas (C₃H₈) measured under the same conditions? [NEET 2008]

1. 7 L
2. 6 L
3. 5 L
4. 10 L

View Solution

Question 20:

The number of moles of KMnO₄ that will be needed to react with one mole of sulphite ion in acidic solution is [NEET 2007]

NEET Chemistry Paper Pattern

​The National Testing Agency (NTA) has revised the NEET UG 2025 exam pattern, reverting to the pre-COVID format. The NEET UG 2025 Chemistry section is structured to assess both theoretical knowledge and application-based understanding. Below is the detailed paper pattern for Chemistry in NEET 2025:

• Total Questions: 45
• Total Marks: 180
• Question Type: Multiple Choice Questions (MCQs)
• Marking Scheme:
  • +4 marks for each correct answer
  • -1 mark for each incorrect answer
  • 0 marks for unanswered questions

Chapter-Wise Distribution and Weightage Analysis

The Chemistry part of NEET UG 2025 has a total of 45 questions for 180 marks. It is further divided into three important branches: Physical Chemistry, Inorganic Chemistry, and Organic Chemistry. Each branch will approximately be 30-35% of the total Chemistry section.

Physical Chemistry includes questions that provide numerical problems. Inorganic Chemistry generally consists only of concepts with a huge part of it being memorization. Organic Chemistry is simply based on reaction mechanisms, named reactions, and perfect conceptualization.

NCERT is the main textbook that all students should focus on. Students should make sure to focus primarily on the fundamental concepts, practice numerical problems, and take mock tests as often as they can to build speed and accuracy. Students should consistently be reading, especially on theoretical topics like Chemical Bonding, Periodic Trends, and Coordination Compounds.

Detailed Topic-Wise Weightage for Chemistry in NEET UG 2025

Physical Chemistry (Class 11)

Physical Chemistry (Class 12)

Inorganic Chemistry (Class 11)

Inorganic Chemistry (Class 12)

Organic Chemistry (Class 11)

Organic Chemistry (Class 12)

NEET Question Paper 2024 PDF with Answer Key and Solution

NEET 2024 Question Paper PDF Code R

NEET 2024 Question Paper PDF Code Q

NEET 2024 Question Paper PDF Code T

NEET 2024 Question Paper PDF Code S

NEET Question Paper 2023 PDF Download with Solution

Here are NEET 2023 question paper of all the sets:

NEET Question Paper 2023 Set E

NEET 2023 Question Paper Set F

Question paper pdfs for F1, F2, F3, F4, F5, and F6 are available for download.

NEET 2023 Question Paper Set G

Question paper pdfs for G1, G2, G3, G4, G5, and G6 are available for download.

NEET 2023 Question Paper Set H

Question paper pdfs for H1, H2, H3, H4, H5, and H6 are available for download.

NEET Manipur Question Paper 2023 PDF Download

NEET Question Paper 2023 PDF Download in Hindi

NEET Question Paper 2022 in English

NEET 2022 Question Paper PDF for all paper codes is available for download.

NEET Question Paper 2022 Set Q

NEET 2022 question paper pdfs for Q1, Q2, Q3, Q4, Q5, and Q6 are available for download.

NEET Question Paper 2022 Set R

NEET Question Paper 2022 Set S

NEET Question Paper 2022 Set T

NEET Question Paper 2021 in English

It was for the first time in 2021 that NTA conducted NEET in 13 languages. Given below are the links to download question paper with solutions PDF in all the 13 languages for all paper codes.

NEET Question Paper 2021 Set M

NEET Question Paper 2021 Set N

NEET Question Paper 2021 Set O

NEET Question Paper 2021 Set P

NEET Question Paper 2020 in English- Set E, F, G, H

NEET Question Paper 2019

Frequently Asked Questions

Q1. Is Some Basic Concept of Chemistry there for NEET?

The important topics of this concept which can be covered are Mole Concept, Stoichiometry, Empirical and Molecular Formula, Laws of Chemical Combination (like the Law of Conservation of Mass, Law of Definite Proportions, etc.), Molar Mass Calculations, Percentage Composition

Although it doesn't carry a very heavy weightage (around 4% of the total marks), this chapter is fundamental for understanding other advanced chemistry topics and solving numerical problems in NEET. It's important for building a solid foundation in physical chemistry.

Make sure you understand these basic concepts as they are repeatedly applied throughout the entire chemistry syllabus.

Q2. How is 160 NEET scored in Chemistry?

The next step in achieving a 160 score in Chemistry must be solving previous year papers and mock tests to increase the speed. Regular practice with focussed schedule will help you score 160 in Chemistry.

Q3. Is NCERT enough for some basic concept in chemistry?

Answer. Yes, NCERT is generally enough for the chapter Some Basic Concepts of Chemistry for NEET preparation. The majority of the questions in NEET are based on concepts and explanations found in the NCERT textbooks. It provides a clear understanding of essential topics like the Mole Concept, Stoichiometry, Laws of Chemical Combination, and more.

Q4. How many questions come from some basic concept in chemistry?

Answer. In NEET UG, approximately 2-3 questions are asked from the chapter "Some Basic Concepts of Chemistry".

Q5. What is the weightage of some basic concept in chemistry in NEET?

Answer. The chapter "Some Basic Concepts of Chemistry" in NEET UG holds a 4% weightage in the exam. Although the weightage is moderate, the concepts are fundamental for understanding more advanced topics in Physical Chemistry and can help you solve various problems in the exam.

Q6. Is p-block there for NEET 2025?

Answer. Yes, p-block elements are part of the NEET 2025 syllabus. The topic covers Group 13 to Group 18 elements, their properties, reactions, and compounds. It is an important section in Inorganic Chemistry and is frequently tested in NEET.

Q7. Is the mole concept difficult?

Answer. At first, the Mole Concept can be difficult, but it gets easier with practice and a firm grasp of the fundamentals. Understanding ideas like molar mass, Avogadro's number, and how to convert between grams, moles, and molecules is crucial. It will become a significant and manageable topic for NEET after you understand the formulas and practice enough problems. Even though it could appear challenging at first, with constant practice and effort, but, it's not.