Acetylene is actually dissolved in the acetone in the bottle for safety purposes. Otherwise in a liquid state, it's much more explosive.
http://www.answers.com/topic/acetylene
Correct. As I stated in another reply. I was trying to say it in shorthand and misstated. Acetylene will blow on its own if not dissolved into the acetone. Exothermic reaction, or something like that, as I recall.