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Some Basic Concepts of Chemistry · Question 29

JEE Main 2025 (Online) 2nd April Morning ShiftMCQEasy📈 Topic in 13% papers+4−1
1

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

Answer

(3) 30

Solution

Mass of C = 1244 1.46 = 0.398 g

Mass of H = 218 0.567 = 0.063 g

Mass of O = 1.0 - (0.398 + 0.063) = 0.539 g

Moles: C = 0.39812 = 0.0332, H = 0.0631 = 0.063, O = 0.53916 = 0.0337

Simplest ratio C : H : O 1 : 2 : 1

Empirical formula = CH2O

Empirical formula mass = 12 + 2 + 16 = 30 g

Answer: (3)

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2

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)

JEE Main 2025 (Online) 2nd April Morning Shift
3

'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]
JEE Main 2025 (Online) 2nd April Evening Shift
4

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
5

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
6

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
7

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
JEE Main 2025 (Online) 28th January Evening Shift

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