posted by Molly(its urgent) .
Helium - oxygen mixture is used by deep sea divers in preference to nitrogen - oxygen mixture. Why?
Think about blood being mostly water. Now look at the solubility of He vs Nitrogen at 10C
And as one comes up from the depths, pressure is reduced, and the excess gas comes out of solution and can block blood vessels (esp in the brain).
Which is the most desirable gas to be dissolved in the blood?
Why isn't pure oxygen used in the breathing mix? Think on that.
a quick google search on helium diving will answer your question
nitrogen narcosis and the bends.
While under great pressure, the most abundant gas in our atmosphere (over 79%) of nitrogen slows down the mental processes of man.
His condition may be similar to alcohol intoxication.