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Some Basic Concepts of Chemistry

JEE Main 2025 (Online) 29th January Morning ShiftMCQEasy📈 Topic in 3% papers+4−1
Ques. 1JEE Main 2025, 29 January (Morning Shift)

Choose the correct statements. Choose the correct answer from the options given below :

  1. (B), (C) and (D) Only
  2. (A), (B) and (C) Only
  3. (C), (D) and (E) Only
  4. (A), (D) and (E) Only

Answer

(3) (C), (D) and (E) Only

Solution

(A) Incorrect. As per NCERT, mass is the amount of matter present in a substance; weight is the force exerted by gravity on an object.

(B) Incorrect. This is the definition of weight, not mass.

(C) Correct. Volume is the amount of space occupied by a substance.

(D) Correct. Temperatures below 0°C (negative values) are possible on the Celsius scale; 0 K is the lowest possible temperature, so negative values are not possible on the Kelvin scale.

(E) Correct. Precision refers to the closeness of various measurements for the same quantity (accuracy is agreement with the true value).

(C), (D) and (E) only

Answer: (3)

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Ques. 2JEE Main 2025, 29 January (Evening Shift)

0.1 M solution of KI reacts with excess of H2SO4 and KIO3 solutions. According to equation 5I- + IO3- + 6H+ 3I2 + 3H2O Identify the correct statements : Choose the correct answer from the options given below :

  1. (C) and (D) only
  2. (A) and (B) only
  3. (B) and (C) only
  4. (A) and (D) only
Ques. 3JEE Main 2025, 28 January (Morning Shift)

The molarity of a 70\% (mass/mass) aqueous solution of a monobasic acid (X) is 10-1 M (Nearest integer) [Given: Density of aqueous solution of (X) is 1.25 g mL-1 Molar mass of the acid is 70 g mol-1]

Ques. 4JEE Main 2025, 28 January (Morning Shift)

Quantitative analysis of an organic compound (X) shows following % composition. C : 14.5\% Cl : 64.46\% H : 1.8\% Empirical formula mass of the compound (X) is 10-1 (Given molar mass in g mol-1 of C : 12, H : 1, O : 16, Cl : 35.5)

Ques. 5JEE Main 2025, 28 January (Evening Shift)

Concentrated nitric acid is labelled as 75% by mass. The volume in mL of the solution which contains 30 g of nitric acid is . Given : Density of nitric acid solution is 1.25 g/mL.

  1. 32
  2. 40
  3. 55
  4. 45
Ques. 6JEE Main 2025, 24 January (Morning Shift)

Consider the following reaction occurring in the blast furnace: Fe3O4(s) + 4CO(g) 3Fe(l) + 4CO2(g) 'x' kg of iron is produced when 2.32 103 kg Fe3O4 and 2.8 102 kg CO are brought together in the furnace. The value of 'x' is . (nearest integer) Given: molar mass of Fe3O4 = 232 g mol-1 molar mass of CO = 28 g mol-1 molar mass of Fe = 56 g mol-1

Ques. 7JEE Main 2025, 24 January (Morning Shift)

Xg of benzoic acid on reaction with aq NaHCO3 released CO2 that occupied 11.2 L volume at STP. X is g.

Ques. 8JEE Main 2025, 24 January (Evening Shift)

The elemental composition of a compound is 54.2\% C, 9.2\% H and 36.6\% O. If the molar mass of the compound is 132 g mol-1, the molecular formula of the compound is : [Given : The relative atomic mass of C:H:O=12:1:16]

  1. C4H8O2
  2. C6H12O6
  3. C4H9O3
  4. C6H12O3
Ques. 9JEE Main 2025, 23 January (Morning Shift)

What amount of bromine will be required to convert 2 g of phenol into 2,4,6-tribromophenol? (Given molar mass in g mol-1 of C, H, O, Br are 12, 1, 16, 80 respectively )

  1. 6.0 g
  2. 10.22 g
  3. 20.44 g
  4. 4.0 g
Ques. 10JEE Main 2025, 23 January (Morning Shift)

2.8 10-3 mol of CO2 is left after removing 1021 molecules from its ' x ' mg sample. The mass of CO2 taken initially is Given: NA = 6.02 1023 mol-1

  1. 98.3 mg
  2. 196.2 mg
  3. 150.4 mg
  4. 48.2 mg
Ques. 11JEE Main 2025, 23 January (Evening Shift)

0.01 mole of an organic compound (X) containing 10\% hydrogen, on complete combustion produced 0.9 g H2O. Molar mass of (X) is g mol-1.

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