1.

Unlikeordinary fire thermite fire cannot be stoppedpouringwater. Explain .

Answer»

Solution :In ordinary fire, the water not only DECREASES the temperatureof the burningmaterial, it alsocuts off the SUPPLY of `O_(2)`. Howeverin thermite REACTION.
`2Al + Fe_(2)O_(3) overset("Heat")rarr Al_(2)O_(3) + 2Fe`
the oxygenneeded for REACTIONIS suppliedby the metaloxide (i.e,`Al_(2)O_(3)`), thereforecutting off thesupplyof atomospheric oxygehas no effect. Further, at high temperature(around `1270-1300 K`), Al reacts with `H_(2)O`to produce `H_(2)O` to produce `H_(2)`gas whichhelps to spread ratherthan extinguishing the fire.
`2Al + 3H_(2)Ooverset(11270-1300K)rarr Al_(2)O_(3) + 3H_(2)`


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