JEE Main2014ChemistrySome Basic Concepts of ChemistryActual

The ratio of masses of oxygen and nitrogen in a particular gaseous mixture is 1 : 4. The ratio of number of their molecules is:

Options

A1 : 4
B7 : 32
C1 : 8
D3 : 16

Correct answer

B. 7 : 32

Step-by-step solution

Let the mass of oxygen be x gm ∴   Mass of nitrogen = 4 x gm Number of molecules = 6.023 x 10 23 x number of moles ∴   Ratio = 6.023 × 1 0 2 3 × no. of moles of oxygen 6.023 × 1 0 2 3 × no. of moles of nitrogen = m O 2 M O 2 m N 2 M N 2 = x 3 2 4 x 2 8 = 7 3 2 = 7 : 32

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