|MadSci Network: Chemistry|
Depriving a fire of Oxygen will put it out. However when Hydrogen reacts with Oxygen to make water it doesnít make nice, cool, liquid water. It produces a rather hot fire of its own and high temperature water vapor, or steam if you will, is the result. As a rather extreme example of this, the fire you see from the main engines of the space shuttle is a Hydrogen Oxygen reaction. So no we canít really put out a forest fire this way.
Liquid water is often thought of as the material to use for putting out fire. It wonít burn because it has already combined with Oxygen. It puts out fire primarily for one or both of two reasons. It can lower the fuel below its ignition temperature and it can smother the fuel from further contact with Oxygen. If a fire is big enough though it may be able to evaporate the water before it can have much effect and in fact if the fire is hot enough it can even separate the water back into Hydrogen and Oxygen. For big fires then the fire fighters often have to deny the fire fuel by making fire breaks in one way or another rather than trying to put it all out directly.
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