The gaseous mixture used by deep sea divers for respiration is

Options

A. `O_(2) + He`
B. `O_(2) + Xe`
C. `O_(2) + Ar`
D. `O_(2) + N_(2)`

Answer

To solve the question regarding the gaseous mixture used by deep sea divers for respiration, we can follow these steps:

### Step 1: Understand the Environment
Deep sea divers operate in high-pressure underwater environments. As they descend, the pressure increases significantly.

**Hint:** Consider how pressure affects gas behavior and solubility in liquids.

### Step 2: Identify Common Gases Used
The common gases that are considered for deep-sea diving include Oxygen (O2) and various inert gases. The options provided are:
1. O2 and He (Helium)
2. O2 and Ar (Argon)
3. O2 and N2 (Nitrogen)

**Hint:** Think about the properties of these gases, especially their solubility and effects under pressure.

### Step 3: Consider the Effects of Nitrogen
Nitrogen (N2) is often used in diving mixtures but poses a risk. Under high pressure, nitrogen can dissolve in the bloodstream. When divers ascend, the pressure decreases, causing nitrogen to come out of solution rapidly, which can lead to decompression sickness, also known as "the bends."

**Hint:** Recall the physiological effects of nitrogen when divers ascend too quickly.

### Step 4: Evaluate the Safe Alternatives
To avoid the risks associated with nitrogen, divers use a mixture of Oxygen and Helium. Helium is an inert gas that does not dissolve in the body in the same way nitrogen does, reducing the risk of decompression sickness.

**Hint:** Consider why an inert gas like Helium would be preferable for deep-sea diving.

### Step 5: Conclusion
Based on the above reasoning, the correct gaseous mixture used by deep sea divers for respiration is Oxygen and Helium.

**Final Answer:** The correct answer is option 1: O2 and He (Helium).