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Some Basic Concepts of Chemistry

Previous year questions with solutions · 2025 – 2026

45Questions
35Papers covered
3.79%Weightage 2026▼ 33.3% vs last year
Year-wise statistics questions · papers · average per paper · weightage
YearQuestionsPapersAvg / paperWeightage
202618190.953.79% ▼ 33.3% vs last year
202527191.45.68%

45 questions · newest paper first · page 1 of 2

Ques. 1JEE Main 2026, 8 April (Evening Shift)

Match List - I with List - II. Choose the correct answer from the options given below :

  1. A-IV, B-III, C-I, D-II
  2. A-III, B-II, C-IV, D-I
  3. A-III, B-IV, C-II, D-I
  4. A-III, B-IV, C-I, D-II
Ques. 2JEE Main 2026, 6 April (Morning Shift)

An oxide of iron contains 69.9% iron, its empirical formula, is: (Given : Molar mass of Fe and O are 56 and 16 g mol-1 respectively.)

  1. FeO
  2. Fe2O3
  3. Fe3O4
  4. FeO3
Ques. 3JEE Main 2026, 6 April (Evening Shift)

Which of the following contain the same number of atoms? (Given : Molar mass in g mol-1 of H, He, O and S are 1, 4, 16 and 32 respectively) Choose the correct answer from the options given below :

  1. A and B only
  2. B and C only
  3. C and D only
  4. A, C and E only
Ques. 4JEE Main 2026, 5 April (Morning Shift)

How many grams of residue is obtained by heating 2.76 g of silver carbonate? (Given : Molar mass of C, O and Ag are 12, 16 and 108 g mol-1 respectively)

  1. 1.08 g
  2. 2.16 g
  3. 3.24 g
  4. 4.32 g
Ques. 5JEE Main 2026, 5 April (Evening Shift)

What volume of hydrogen gas at STP would be liberated by action of 50 mL of H2SO4 of 50% purity (density = 1.3 g mL-1) on 20 g of zinc? Given : Molar mass of H, O, S, Zn are 1, 16, 32, 65 g mol-1 respectively.

  1. 5.824 L
  2. 7.428 L
  3. 6.892 L
  4. 8.375 L
Ques. 6JEE Main 2026, 4 April (Morning Shift)

Number of moles and number of molecules in 1.4187 L of SO2 at STP respectively are

  1. 0.1266; 3.812 1022
  2. 0.0633; 3.812 1022
  3. 0.1266; 7.6238 1022
  4. 0.0633; 7.6238 1022
Ques. 7JEE Main 2026, 4 April (Evening Shift)

The 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 :

  1. C > A > B
  2. C > B > A
  3. B > C > A
  4. B > A > C
Ques. 8JEE Main 2026, 2 April (Morning Shift)

The mass of iron converted into Fe3O4 by the action of 18 g of steam is : (Given : Molar mass of H, O and Fe are 1, 16 and 56 g mol-1 respectively) Assume iron is present in excess :

  1. 2.1 g
  2. 4.2 g
  3. 21 g
  4. 42 g
Ques. 9JEE Main 2026, 2 April (Evening Shift)

The ratio of mass percentage (w/w) of C : H in a hydrocarbon is 12 : 1. It has two carbon atoms. The weight (in g) of CO2(g) formed when 3.38 g of this hydrocarbon is completely burnt in oxygen is : (Given : Molar mass in g mol-1 C : 12, H : 1, O : 16)

  1. 5.68
  2. 11.44
  3. 22.74
  4. 17.05
Ques. 10JEE Main 2026, 28 January (Evening Shift)

For the given reaction; CaCO3 + 2HCl CaCl2 + H2O + CO2 If 90 g CaCO3 is added to 300 mL of HCl which contains 38.55% HCl by mass and has density 1.13 g mL-1, then which of the following option is correct? Given molar mass of H, Cl, Ca and O are 1, 35.5, 40 and 16 g mol-1 respectively.

  1. 64.97 g of HCl remains unreacted
  2. 60.32 g of HCl remains unreacted
  3. 32.85 g of CaCO3 remains unreacted
  4. 97.30 g of HCl reacted
Ques. 11JEE Main 2026, 24 January (Evening Shift)

A student has planned to prepare acetanilide from aniline using acetic anhydride. The student has started from 9.3 g of aniline. However, the student has managed to obtain 11 g of dry acetanilide. The % yield of this reaction is :-

  1. 59.5\%
  2. 72.5\%
  3. 97.5\%
  4. 81.5\%
Ques. 12JEE Main 2026, 23 January (Morning Shift)

x mg of pure HCl was used to make an aqueous solution. 25.0 mL of 0.1 M Ba(OH)2 solution is used when the HCl solution was titrated against it. The numerical value of x is 10-1. (Nearest integer) Given : Molar mass of HCl and Ba(OH)2 are 36.5 and 171.0 g mol-1 respectively.

Ques. 13JEE Main 2026, 22 January (Morning Shift)

In the reaction, 2Al(s) + 6HCl(aq) 2Al3+(aq) + 6Cl-(aq) + 3H2(g)

  1. 12 L HCl(aq) is consumed for every 6 L H2(g) produced.
  2. 11.2 L H2(g) at STP is produced for every mole of HCl consumed.
  3. 33.6 L H2(g) is produced regardless of temperature and pressure for every mole of Al that reacts.
  4. 67.2 L H2(g) at STP is produced for every mole of Al that reacts.
Ques. 14JEE Main 2026, 22 January (Evening Shift)

At T(K), 100 g of 98\% H2SO4 (w/w) aqueous solution is mixed with 100 g of 49\% H2SO4 (w/w) aqueous solution. What is the mole fraction of H2SO4 in the resultant solution? (Given : Atomic mass H = 1 u; S = 32 u; O = 16 u). (Assume that temperature after mixing remains constant)

  1. 0.9
  2. 0.663
  3. 0.1
  4. 0.337
Ques. 15JEE Main 2026, 22 January (Evening Shift)

A + 2B AB2 36.0 g of 'A' (Molar mass : 60 g mol-1) and 56.0 g of 'B' (Molar mass : 80 g mol-1) are allowed to react. Which of the following statements are correct ? Choose the correct answer from the options given below :

  1. A and C Only
  2. A and B Only
  3. C and D Only
  4. B and D Only
Ques. 16JEE Main 2026, 21 January (Morning Shift)

14.0 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? [Given : Molar mass in g mol-1 of Ca – 40, Cl – 35.5, H – 1]

  1. The limiting reagent is calcium metal.
  2. 33.3 g of CaCl2 is produced.
  3. 7.84 L of H2 gas is evolved.
  4. 0.35 mol of H2 gas is evolved.
Ques. 17JEE Main 2026, 21 January (Morning Shift)

80 mL of a hydrocarbon on mixing with 264 mL of oxygen in a closed U-tube undergoes complete combustion. The residual gases after cooling to 273 K occupy 224 mL. When the system is treated with KOH solution, the volume decreases to 64 mL. The formula of the hydrocarbon is :

  1. C2H2
  2. C2H4
  3. C4H10
  4. C2H6
Ques. 18JEE Main 2026, 21 January (Evening Shift)

Aqueous HCl reacts with MnO2(s) to form MnCl2(aq), Cl2(g), and H2O(l). What is the weight (in g) of Cl2 liberated when 8.7 g of MnO2(s) is reacted with excess aqueous HCl solution? (Given Molar mass in g mol-1 Mn = 55, Cl = 35.5, O = 16, H = 1)

  1. 14.2
  2. 21.3
  3. 7.1
  4. 71
Ques. 19JEE Main 2025, 8 April (Evening Shift)

20 mL of sodium iodide solution gave 4.74 g silver iodide when treated with excess of silver nitrate solution. The molarity of the sodium iodide solution is M. (Nearest Integer value) (Given : Na = 23, I = 127, Ag = 108, N = 14, O = 16 g mol-1)

Ques. 20JEE Main 2025, 7 April (Morning Shift)

Thyroxine, the hormone, has the structure given below [figure] The percentage of iodine in thyroxine is %. (nearest integer) (Given molar mass in g mol-1 C : 12, H : 1, O : 16, N : 14, I : 127)

Ques. 21JEE Main 2025, 7 April (Evening Shift)

Butane reacts with oxygen to produce carbon dioxide and water following the equation given below. C4H10(g) + 132O2(g) 4CO2(g) + 5H2O(l) If 174.0 kg of butane is mixed with 320.0 kg of O2, the volume of water formed in liters is . (Nearest integer) [Given : (a) Molar mass of C, H, O are 12, 1, 16 g mol-1 respectively, (b) Density of water = 1 g mL-1]

Ques. 22JEE Main 2025, 4 April (Morning Shift)

Fortification of food with iron is done using FeSO4 7H2O. The mass in grams of the FeSO4 7H2O required to achieve 12 ppm of iron in 150 kg of wheat is (Nearest integer) [Given: Molar mass of Fe, S and O respectively are 56, 32 and 16 g mol-1]

Ques. 23JEE Main 2025, 4 April (Evening Shift)

The amount of calcium oxide produced on heating 150 kg limestone (75% pure) is kg. (Nearest integer) Given: Molar mass (in g mol-1) of Ca-40, O-16, C-12

Ques. 24JEE Main 2025, 3 April (Morning Shift)

Among 10-9 g (each) of the following elements, which one will have the highest number of atoms? Element: Pb, Po, Pr and Pt

  1. Pr
  2. Pt
  3. Po
  4. Pb
Ques. 25JEE Main 2025, 3 April (Evening Shift)

Mass 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 24 g mol-1.

  1. 0.24 mg
  2. 235.7 g
  3. 2.444 g
  4. 236 mg
Ques. 26JEE Main 2025, 3 April (Evening Shift)

10 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 flask of 100 mL containing 2 moles of HCl and made the volume up to the mark with distilled water. The solution in this flask is :

  1. 0.2 M NaCl solution
  2. 20 M HCl solution
  3. Neutral solution
  4. 10 M HCl solution
Ques. 27JEE Main 2025, 3 April (Evening Shift)

X g of nitrobenzene on nitration gave 4.2 g of m-dinitrobenzene. X = g. (nearest integer) [Given : molar mass (in g mol-1) C : 12, H : 1, O : 16, N : 14]

Ques. 28JEE Main 2025, 2 April (Morning Shift)

CaCO3(s)+2HCl(aq) CaCl2(aq)+CO2(g)+H2O(l) Consider the above reaction, what mass of CaCl2 will be formed if 250 mL of 0.76 M HCl reacts with 1000 g of CaCO3 ? (Given : Molar mass of Ca, C, O, H and Cl are 40, 12, 16, 1 and 35.5 g mol-1, respectively)

  1. 3.908 g
  2. 2.636 g
  3. 10.545 g
  4. 5.272 g
Ques. 29JEE Main 2025, 2 April (Morning Shift)

On complete combustion 1.0 g of an organic compound (X) gave 1.46 g of CO2 and 0.567 g of H2O. The empirical formula mass of compound (X) is g. (Given molar mass in g mol-1 C : 12, H : 1, O : 16)

  1. 60
  2. 45
  3. 30
  4. 15
Ques. 30JEE Main 2025, 2 April (Morning Shift)

0.1 mol of the following given antiviral compound (P) will weigh 10-1 g (nearest integer). [figure] (Given : molar mass in g mol-1 H : 1, C : 12, N : 14, O : 16, F : 19, I : 127)