The inert gas used instead of nitrogen in the air for deep-sea divers is:

Deep-sea diving involves breathing gases under high-pressure conditions. At great depths, nitrogen, which is a major component of air, can cause nitrogen narcosis, a dangerous condition affecting the nervous system and causing symptoms similar to intoxication. To prevent this, an inert gas like helium is used instead of nitrogen in breathing mixtures.

Helium (He) is a light, non-toxic, chemically inert gas with low density. Its low solubility in body tissues reduces the risk of decompression sickness, also known as “the bends,” which occurs when dissolved gases form bubbles in the bloodstream during rapid ascent. Helium allows divers to breathe safely at high pressures, maintaining clear thinking and reducing physical strain. It is often mixed with oxygen in specialized breathing mixtures called heliox, which are used for deep dives below 100 meters.

Other inert gases like argon, xenon, or krypton are not preferred. Argon is denser and harder to breathe at depth, increasing work of breathing. Xenon and krypton are rare, expensive, and also denser than helium, making them unsuitable for practical deep-sea diving.

The use of helium in diving demonstrates the application of physics principles, including gas behavior under pressure, buoyancy, and solubility, as well as human physiology under extreme conditions. Understanding why helium is chosen over nitrogen helps students learn how inert gases and gas mixtures are applied in real-life scenarios.

In summary, the inert gas used instead of nitrogen for deep-sea divers is helium, ensuring safety, reducing narcosis risk, and allowing efficient respiration at high underwater pressures. This knowledge is a key part of physics and everyday science, connecting gas laws with practical applications.