Question

when a lot of Dry Powder of a substance 'x' is released over a fire the fire gets 16 extinguished. 1. name the substance 'x'
2. how does the substance extinguish the fire
3. name another substance which behaves like 'x'

Answer 1

1) Is that Dry ice power ? 

2)   Solid CO2 is called Dry Ice powder.  When it is sprayed over fire, then it immediately vaporizes. It shields fresh air from the burning substance. It is heavier than Oxygen. So CO2 stays closer to the burning substance.

3)  There are other substances like :  Salt Na Cl, Copper salt power, Barium Chloride powder . They are usable too. They form a crust layer on the top of metals which are burning. Then shield them from Oxygen.

Answer 2

the answer is solid carbon dioxide