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Chemistry - Some Basic Concepts of Chemistry

Practise 206 JEE Main previous year questions on Some Basic Concepts of Chemistry, compiled from papers spanning 2002 to 2026. Each question is pulled directly from the actual exam paper it appeared in, so you're practising in the exact style and difficulty JEE Main tests.

Some Basic Concepts of Chemistry has been asked in 22 of the 25 years of JEE Main papers analysed (2002–2026), with 206 questions in all. 27% of them were easy, 61% moderate and 12% tough. Most of its questions came from 2022, with 29 questions that year. In the last three years (2024–2026) it had 48 questions across 49 papers, about 1 per paper.

The chapter's 5 topics are not weighted equally: Quantitative measures in chemical equations (86 questions, 42%), Concentration terms (60 questions, 29%), and Mole concept (46 questions, 22%) have been asked the most. Quantitative measures in chemical equations has also led over the last five years, with 50 questions. Quantitative measures in chemical equations has produced the most tough questions (14).

  1. 1Match List-I with List-II. List-I Mass of substance List-II Number of atoms A. mg water I. B. mg sulphuric acid II. C. mg carbon III. D. mg 08 Apr, 2026 (E)Mole concept
  2. 2An oxide of iron contains iron, its empirical formula, is: (Given: Molar mass of Fe and O are and g mol respectively.)06 Apr, 2026 (M)Quantitative measures in chemical equations
  3. 3Which of the following contain the same number of atoms ? (Given : Molar mass in g mol of H, He, O and S are and respectively) A. g of O gas06 Apr, 2026 (E)Mole concept
  4. 4How many grams of residue is obtained by heating g of silver carbonate? (Given: Molar mass of C, O and Ag are , and g mol respectively)05 Apr, 2026 (M)Mole concept
  5. 5What volume of hydrogen gas at STP would be liberated by action of of of purity (density ) on of zinc ? Given : Molar mass of H, O, S, Zn ar05 Apr, 2026 (E)Quantitative measures in chemical equations
  6. 6Number of moles and number of molecules in L of at STP respectively are:04 Apr, 2026 (M)Mole concept
  7. 7The correct order of total number of atoms present in (A) moles of cyclohexane (B) g of sucrose (C) L of dihydrogen at STP is:04 Apr, 2026 (E)Mole concept
  8. 8The ratio of mass percentage (w/w) of C : H in a hydrocarbon is . It has two carbon atoms. The weight (in g) of formed when g of this hydroc02 Apr, 2026 (E)Mole concept
  9. 9For the given reaction: If is added to 300 mL of HCl which contains by mass and has density , then which of the following option is correct 28 Jan, 2026 (E)Quantitative measures in chemical equations
  10. 10In the reaction,22 Jan, 2026 (M)Quantitative measures in chemical equations
  11. 1136.0 g of 'A' (Molar mass: ) and 56.0 g of ' (Molar mass: ) are allowed to react. Which of the following statements are correct ? A. 'A' is 22 Jan, 2026 (E)Quantitative measures in chemical equations
  12. 1214.0 g of calcium metal is allowed to react with excess HCl at 1.0 atm pressure and 273 K. Which of the following statements is incorrect? [21 Jan, 2026 (M)Quantitative measures in chemical equations
  13. 1380 mL of a hydrocarbon on mixing with 264 mL of oxygen in a closed U-tube undergoes complete combustion. The residual gases after cooling to21 Jan, 2026 (M)Quantitative measures in chemical equations
  14. 14Aqueous HCl reacts with to form and . What is the weight (in g) of liberated when 8.7 g of is reacted with excess aqueous HCl solution? (Giv21 Jan, 2026 (E)Quantitative measures in chemical equations
  15. 1520 mL of sodium iodide solution gave 4.74 g silver iodide when treated with excess of silver nitrate solution. The molarity of the sodium io08 Apr, 2025 (E)Quantitative measures in chemical equations
  16. 16On combustion 0.210 g of an orgainc compound containing and O gave and 0.307 . The percentages of hydrogen and oxygen in the given organic c08 Apr, 2025 (E)Quantitative measures in chemical equations
  17. 17An organic compound weighing 500 mg , produced 220 mg of . on complete combustion. The percentage composition of carbon in the compound is _07 Apr, 2025 (M)Quantitative measures in chemical equations
  18. 18Butane reacts with oxygen to produce carbon dioxide and water following the equation given below If 174.0 kg of butane is mixed with 320.0 k07 Apr, 2025 (E)Quantitative measures in chemical equations
  19. 19Fortification of food with iron is done using . The mass in grams of the required to achieve 12 ppm of iron in 150 kg of wheat is ____ (Near04 Apr, 2025 (M)Mole concept
  20. 20The amount of calcium oxide produced on heating 150 kg limestone ( pure) is ______ kg. (Nearest integer) Given : Molar mass (in ) of Ca-40, 04 Apr, 2025 (E)Quantitative measures in chemical equations
  21. 21Among (each) of the following elements, which one will have the highest number of atoms? Element : and Pt03 Apr, 2025 (M)Mole concept
  22. 22Mass of magnesium required to produce 220 mL of hydrogen gas at STP on reaction with excess of dil. HCl is Given : Molar mass of Mg is .03 Apr, 2025 (E)Quantitative measures in chemical equations
  23. 230.1 mol of the following given antiviral compound \(( {P})\) will weigh ________ \( 10^{-1} {~g}\) (Given : molar mass in \( {g} {mol}^{-1} 02 Apr, 2025 (M)Mole concept
  24. 24\( {CaCO}_3( {~s})+2 {HCl}( {aq}) {CaCl}_2( {aq})+ {CO}_2( {~g}) {H}_2 {O}( {l})\) Consider the above reaction, what mass of \( {CaCl}_2\) w02 Apr, 2025 (M)Quantitative measures in chemical equations
  25. 25On complete combustion 1.0 g of an organic compound (X) gave 1.46 g of \( {CO}_2\) and 0.567 g of \( {H}_2 {O}\). The empirical formula mass02 Apr, 2025 (M)Quantitative measures in chemical equations
  26. 26Consider the above sequence of reactions. 151 g of 2-bromopentane is made to react. Yield of major product P is whereas Q is . Mass of produ02 Apr, 2025 (E)Quantitative measures in chemical equations
  27. 27Choose the correct statements. (A) Weight of a substance is the amount of matter present in it. (B) Mass is the force exerted by gravity on 29 Jan, 2025 (M)Quantitative measures in chemical equations
  28. 28The molarity of a (mass mass) aqueous solution of a monobasic acid is __________ M(Nearest integer) [Given: Density of aqueous solution of (28 Jan, 2025 (M)Concentration terms
  29. 29Quantitative analysis of an organic compound (X) shows following % composition. C : Cl : 64.46% H: 1.8 % (Empirical formula mass of the comp28 Jan, 2025 (M)Quantitative measures in chemical equations
  30. 30Concentrated nitric acid is labelled as by mass. The volume in mL of the solution which contains 30 g of nitric acid is ____. Given : Densit28 Jan, 2025 (E)Concentration terms
  31. 31Xg of benzoic acid on reaction with aq released that occupied 11.2 L volume at STP. X is _____ g.24 Jan, 2025 (M)Mole concept
  32. 32Consider the following reaction occurring in the blast furnace: ' ' kg of iron is produced when and are brought together in the furnace. The24 Jan, 2025 (M)Quantitative measures in chemical equations
  33. 33The elemental composition of a compound is and . If the molar mass of the compound is , the molecular formula of the compound is : [Given : 24 Jan, 2025 (E)Quantitative measures in chemical equations
  34. 34The hydrocarbon with molar mass and carbon has degree of unsaturation.24 Jan, 2025 (E)Concentration terms
  35. 35of is left after removing molecules from its ' ' mg sample. The mass of taken initially is Given:23 Jan, 2025 (M)Mole concept
  36. 360.01 mole of an organic compound containing hydrogen, on complete combustion produced . Molar mass of is _____ .23 Jan, 2025 (E)Mole concept
  37. 37When 81.0 g of aluminium is allowed to react with 128.0 g of oxygen gas, the mass of aluminium oxide produced in grams is_______ - (Nearest 23 Jan, 2025 (E)Mole concept
  38. 38Density of 3 M NaCl solution is . The molality of the solution is :22 Jan, 2025 (E)Concentration terms
  39. 3920 mL of 2 M NaOH solution is added to 400 mL of 0.5 M NaOH solution. The final concentration of the solution is _______ . (Nearest integer)22 Jan, 2025 (E)Concentration terms
  40. 40Molarity \(( {M})\) of an aqueous solution containing \(x {~g}\) of anhyd. \( {CuSO}_4\) in \(500 {~mL}\) solution at \(32{ }^{ } {C}\) is \09 Apr, 2024 (M)Concentration terms
  41. 41Combustion of glucose \( ( {C}_6 {H}_{12} {O}_6 )\) produces \( {CO}_2\) and water. The amount of oxygen (in g) required for the complete co08 Apr, 2024 (M)Quantitative measures in chemical equations
  42. 42The density of ' \(x\) ' \( {M}\) solution (' \(X\) ' molar) of \( {NaOH}\) is \(1.12 {~g} {~mL}^{-1}\), while in molality, the concentratio06 Apr, 2024 (M)Concentration terms
  43. 43Molality ( \( {m}\) ) of \(3 {M}\) aqueous solution of \( {NaCl}\) is : (Given : Density of solution \(=1.25 {~g} {~mL}^{-1}\), Molar mass i06 Apr, 2024 (E)Concentration terms
  44. 44An organic compound has \(42.1 \%\) carbon, \(6.4 \%\) hydrogen and remainder is oxygen. If its molecular weight is 342, then its molecular 05 Apr, 2024 (M)Quantitative measures in chemical equations
  45. 45\(9.3 {~g}\) of pure aniline is treated with bromine water at room temperature to give a white precipitate of the product ' \( {P}\) '. The 05 Apr, 2024 (M)Quantitative measures in chemical equations
  46. 46The number of moles of methane required to produce \(11 {~g} {CO}_2( {~g})\) after complete combustion is : (Given molar mass of methane in 05 Apr, 2024 (E)Quantitative measures in chemical equations
  47. 47Consider the following reaction: 3 PbCl 2 + 2 NH 4 3 PO 4 → Pb 3 PO 4 2 + 6 NH 4 Cl If 72 mmol PbCl 2 is mixed with 50 mmol of NH 4 3 PO 4 ,01 Feb, 2024 (M)Quantitative measures in chemical equations
  48. 4810 mL of gaseous hydrocarbon on combustion gives 40 mL of CO 2 g and 50 mL of water vapour. Total number of carbon and hydrogen atoms in the01 Feb, 2024 (E)Quantitative measures in chemical equations
  49. 49Number of moles of methane required to produce 22 g CO 2 ( g ) after combustion is x × 10 – 2 moles. The value of x is31 Jan, 2024 (M)Mole concept
  50. 50A sample of CaCO 3 and MgCO 3 weighed 2 .21 g is ignited to constant weight of 1 .152 g . The composition of the mixture is: (Given molar ma31 Jan, 2024 (E)Quantitative measures in chemical equations

Frequently Asked Questions

1.How many questions are available for Some Basic Concepts of Chemistry?

This chapter includes 206 questions compiled from JEE Main papers spanning 2002 to 2026.

2.Are these questions only from JEE Main, or from other exams too?

These are JEE Main questions specifically for the Some Basic Concepts of Chemistry chapter. Questions from other exams like NTA Abhyas (JEE Main) or JEE Advanced are organised separately under their respective exam sections.

3.Is Some Basic Concepts of Chemistry an important chapter for JEE Main Chemistry?

Some Basic Concepts of Chemistry has appeared in 22 of the 25 years of JEE Main papers covered here, with 206 questions across 155 papers - about one per paper it appears in.

4.What is the difficulty level of Some Basic Concepts of Chemistry questions in JEE Main?

Of the 206 questions analysed for this chapter, 27% are easy, 61% moderate and 12% tough. 2022 had the most, with 29 questions.

5.Which topics in Some Basic Concepts of Chemistry should I focus on?

These topics have carried the most weightage in Some Basic Concepts of Chemistry:

  • Quantitative measures in chemical equations - 86 questions (42%)
  • Concentration terms - 60 questions (29%)
  • Mole concept - 46 questions (22%)
  • Quantitative measures in chemical equations has produced the most tough questions (14).
6.Is Some Basic Concepts of Chemistry's weightage in JEE Main going up or down?

Across all 155 papers analysed, Some Basic Concepts of Chemistry has averaged about 1.3 questions per paper. In the last three years (2024–2026), that average has fallen, at about 1.0 questions per paper. Use the year-wise numbers on this page for the exact trend before you decide how much time to give it.