Four flask of 1 litre capacity each are separately filled with gases `H_2,He,O_2` and `O_3`. At the same temperature and pressure, the ratio of the number of atoms of these gases present in different flask would be :

Options

A. 1:1:1:1
B. 2:1:2:3
C. 1:2:1:3
D. 3:2:2:1

Explanation

To solve the problem, we need to determine the ratio of the number of atoms present in 1 liter flasks filled with the gases H₂, He, O₂, and O₃ at the same temperature and pressure.

### Step-by-step Solution:

1. **Understand the Ideal Gas Law**:
The ideal gas law is given by the equation \( PV = nRT \). Since the pressure (P), volume (V), and temperature (T) are the same for all four gases, the number of moles (n) of each gas will also be the same.

2. **Determine the Number of Atoms in Each Gas**:
- For **Hydrogen (H₂)**:
- 1 mole of H₂ contains 2 moles of H atoms (since each molecule of H₂ has 2 hydrogen atoms).
- For **Helium (He)**:
- 1 mole of He contains 1 mole of He atoms (since helium is monatomic).
- For **Oxygen (O₂)**:
- 1 mole of O₂ contains 2 moles of O atoms (since each molecule of O₂ has 2 oxygen atoms).
- For **Ozone (O₃)**:
- 1 mole of O₃ contains 3 moles of O atoms (since each molecule of O₃ has 3 oxygen atoms).

3. **Calculate the Number of Atoms**:
- Hydrogen (H₂): 2 atoms
- Helium (He): 1 atom
- Oxygen (O₂): 2 atoms
- Ozone (O₃): 3 atoms

4. **Set Up the Ratio**:
The ratio of the number of atoms in the flasks is:
\[ \text{H₂ : He : O₂ : O₃} = 2 : 1 : 2 : 3 \]

5. **Simplify the Ratio**:
The ratio can be expressed as:
\[ 2 : 1 : 2 : 3 \]

### Final Answer:
The ratio of the number of atoms of the gases H₂, He, O₂, and O₃ is \( 2 : 1 : 2 : 3 \).