Hydrogen burns with blue flame.Oxygen support burning when two atoms of Hydrogen combines with one atom of oxygen forms water this water put off the flames why?

Answer 1

This is an idiotic question. Drop your class quickly, if this is the norm.

when hydrogen reacts with oxygen, steam is formed, not water.

To put out the flame, either of the reactants has to be removed, which dousing with water will not accomplish, OR the sustaining temperature required for ignition has to be reduced, which water can do by cooling rapidly. But frankly, water would be hard pressed to put out a large size "fire" of H2 and O2, as it is an explosive mixture.

Answer 2

You might want to look at the fire triangle see http://en.wikipedia.org/wiki/Fire_triangle

if fuel, heat or oxygen is removed then a fire dies.

As Bob suggests removing the heat by dowsing with water will put out a fire. Although this is hard to do with a H2/O2 flame as the flame can still still be present underwater (see (Broken Link Removed)

Steam does have an effect on an H2/O2 mixture as it can have the effect of diluting the mixture below the explosive mixture (about 4% H2 in air)