Assertion : Deep sea divers use `He-O_(2)` mixture for breathing
Reason : Unike `N_(2)` He is insoluble in blood ever under high pressure

Options

A. If both (A) and (R ) are correct and (R ) is the correct explanation of (A)
B. If both (A) and (R ) are correct,but (R ) is the correct explanation of (A)
C. If (A) is correct but (R ) is incorrect
D. If (A) is incorrect but (R ) is correct

Answer

To analyze the assertion and reason provided in the question, we can break down the information step by step.

### Step 1: Understanding the Assertion
The assertion states that deep sea divers use a helium-oxygen mixture for breathing. This is a common practice in deep-sea diving because of the properties of helium.

**Hint:** Consider why divers might prefer helium over nitrogen when breathing at great depths.

### Step 2: Understanding the Reason
The reason given is that, unlike nitrogen (N2), helium is insoluble in blood even under high pressure. This is crucial because nitrogen can dissolve in blood under high pressure and can lead to dangerous conditions.

**Hint:** Think about the effects of gas solubility in blood and how it relates to pressure changes experienced by divers.

### Step 3: Analyzing the Implications
When divers descend to great depths, the pressure increases, which can cause nitrogen to dissolve in the blood. If the diver ascends too quickly, this nitrogen can form bubbles, leading to decompression sickness (also known as "the bends"). Helium, being less soluble, does not have this risk.

**Hint:** Reflect on the dangers associated with nitrogen bubbles forming in the bloodstream during rapid ascent.

### Step 4: Conclusion
Both the assertion and reason are correct. The assertion correctly states that deep-sea divers use a helium-oxygen mixture, and the reason explains why helium is preferred over nitrogen due to its low solubility in blood under high pressure.

**Final Answer:** Both the assertion and reason are correct, and the reason provides a valid explanation for the assertion.

### Summary
- **Assertion:** Deep sea divers use a He-O2 mixture for breathing.
- **Reason:** Helium is insoluble in blood under high pressure, unlike nitrogen.
- **Conclusion:** Both statements are correct, and the reason explains the assertion.