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Some Basic Concepts of Chemistry

JEE Main 2025 (Online) 7th April Morning ShiftNumericalEasy📈 Topic in 12% papers+4
Ques. 1JEE 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)

Answer

65

Solution

Counting atoms in the structure: 15 C, 11 H (4 aromatic H, OH, CH2, CH, NH2, COOH), 1 N, 4 O, 4 I

molecular formula C15H11NO4I4

Molar mass = 15(12) + 11(1) + 14 + 4(16) + 4(127)

= 180 + 11 + 14 + 64 + 508 = 777 g mol-1

% I = 508777 100 = 65.38\% 65\%

Answer: 65

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Ques. 2JEE 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. 3JEE 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. 4JEE 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. 5JEE 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. 6JEE 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. 7JEE 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. 8JEE 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. 9JEE 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. 10JEE 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. 11JEE 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)

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