How are inert gases used?

Which gases are used in the respiration of scuba divers?

• as i was saying in the above question which gases are used in the cylinder of scuba divers while going under water.I have options but i don't know the right answer ...show more

• Answer:

  The question has no completely correct answer. Most scuba divers breathe dry compressed air which is 78.08% nitrogen 20.95% oxygen 0.93% argon 0.039% carbon dioxide <0.00273% other gases including neon, helium, methane, krypton, hydrogen, nitrous oxide, carbon monoxide, xenon, ozone, nitrogen dioxide, iodine, and ammonia. A recent trend has been for some recreational scuba divers to use "enriched air" which replaces some nitrogen with oxygen, most often with either 36% or 32% oxygen. Deep divers, and this is well beyond recreational scuba, use more exotic gas mixtures to reduce the risk of decompression sickness, reduce the duration of decompression, reduce nitrogen narcosis and allowing safer deep diving. An industrial diver working at 500 feet would probably breath hydreliox, a mix of mostly helium, with some oxygen and a trace of hydrogen. The best answer is therefore [c] oxygen and helium.