The composition of gaseous mixture used by scuba divers is :-

Options

A. 56.2% `N_2 and 32.1% O_2`
B. `56.2% O_2 and 32.1% N_2`
C. `50.2% N_2 and 38.1% O_2`
D. `50.2% O_2 and 38.1% N_2`

Answer

To solve the question regarding the composition of the gaseous mixture used by scuba divers, we will analyze the provided options and identify the correct one based on known information about scuba diving gas mixtures.

### Step-by-Step Solution:

1. **Understanding the Question**:
- The question asks for the composition of the gaseous mixture used by scuba divers. We need to identify the correct percentages of gases in the mixture.

2. **Analyzing the Options**:
- We have four options:
1. 56.2% N2 and 32.1% O2
2. 56.2% O2 and 32.1% N2
3. 50.2% N2 and 38.1% O2
4. 50.2% O2 and 38.1% N2

3. **Recalling Known Information**:
- Scuba divers typically use a mixture of nitrogen (N2), oxygen (O2), and sometimes helium (He). The common mixture for recreational diving is approximately:
- Nitrogen: 56.2%
- Oxygen: 32.1%
- Helium: 10.1% (not mentioned in the options but is often included in deeper dives).

4. **Identifying the Correct Option**:
- Based on the known composition, the first option (56.2% N2 and 32.1% O2) matches the typical mixture used by scuba divers.
- The other options either have the percentages reversed or do not match the known standard.

5. **Conclusion**:
- Therefore, the correct answer is:
- **56.2% N2 and 32.1% O2** (Option 1).

### Final Answer:
The composition of the gaseous mixture used by scuba divers is **56.2% nitrogen (N2) and 32.1% oxygen (O2)**.

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