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Some Basic Concepts of Chemistry · Question 27

JEE Main 2025 (Online) 3rd April Evening ShiftNumericalEasy📈 Topic in 42% papers+4
1

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]

Answer

3

Solution

C6H5NO2 conc. HNO3/conc. H2SO4 m-C6H4(NO2)2

1 mol of nitrobenzene gives 1 mol of m-dinitrobenzene.

Molar mass of C6H5NO2 = 72 + 5 + 14 + 32 = 123 g mol-1

Molar mass of C6H4(NO2)2 = 72 + 4 + 28 + 64 = 168 g mol-1

moles of m-dinitrobenzene = 4.2168 = 0.025 mol

moles of nitrobenzene needed = 0.025 mol

X = 0.025 123 = 3.075 g 3 g

Answer: 3

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2

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
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3

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
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4

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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5

'x' g of NaCl is added to water in a beaker with a lid. The temperature of the system is raised from 1 C to 25 C. Which out of the following plots, is best suited for the change in the molarity (M) of the solution with respect to temperature? [Consider the solubility of NaCl remains unchanged over the temperature range]

  1. [figure]
  2. [figure]
  3. [figure]
  4. [figure]
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6

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
JEE Main 2025 (Online) 29th January Morning Shift
7

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]

JEE Main 2025 (Online) 28th January Morning Shift
8

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)

JEE Main 2025 (Online) 28th January Morning Shift
9

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
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