By Tri chlorination, three chlorine atoms can replace the 3 hydrogen atoms in propane molecule to give tri-chlorinated products according to the attached picture.
G. H2S contains two hydrogen atoms
Blow a lot of air into it you can stick an air pump and when your done pumping quickly put tape over the hole
The answer is High altitude
The troposphere protect the molecules because there are higher layers on top. This makes life possible on Earth.