Components of gaseous mixture useful for sea divers

Options

A. `O_2 and He`
B. `O_2` and `H_2`
C. `O_2` and `N_2`
D. `O_2` and `CO_2 `

Answer

**Step-by-Step Solution:**

1. **Understanding the Question:**
- The question asks for the components of a gaseous mixture that are useful for sea divers. This mixture needs to ensure safety and efficiency during deep-sea dives.

2. **Analyzing the Options:**
- The options provided are:
1. Oxygen and Helium
2. Oxygen and Hydrogen
3. Oxygen and Nitrogen
4. Oxygen and Carbon Dioxide

3. **Evaluating Each Option:**
- **Option 1: Oxygen and Helium**
- Helium is a noble gas with low intermolecular forces. This means it is less soluble in blood and other bodily fluids. When divers ascend from deep water to the surface, the pressure decreases, and gases can come out of solution. Helium minimizes the risk of "the bends" (decompression sickness) because it does not bubble out of the blood as nitrogen does.

- **Option 2: Oxygen and Hydrogen**
- While hydrogen is a light gas, it is highly flammable and not suitable for breathing at high pressures. This combination is not safe for diving.

- **Option 3: Oxygen and Nitrogen**
- Nitrogen is commonly found in air, but it can cause decompression sickness when divers ascend too quickly. This is because nitrogen can form bubbles in the bloodstream as pressure decreases, leading to potential health risks.

- **Option 4: Oxygen and Carbon Dioxide**
- Carbon dioxide is a waste product of respiration and is not suitable for breathing. High levels of CO2 can lead to respiratory issues and should not be included in a diving mixture.

4. **Conclusion:**
- After evaluating all the options, the best choice for a gaseous mixture useful for sea divers is **Option 1: Oxygen and Helium**. This combination is safe and effective for deep-sea diving due to helium's low solubility and minimal risk of decompression sickness.

**Final Answer:**
- The components of the gaseous mixture useful for sea divers are **Oxygen and Helium**.

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