Question

Why, water cannot be used to extinguish petrol fires?

Answer 1

As water is heavier than petrol, therefore, slips down permitting the petrol to rise to the surface and continue to burn. Besides, the existing temperature is so high that the water poured on the fire evaporates even before it can extinguish the fire. The latter is true if a small quantity of water is poured. Thus the petrol fire cannot be extinguished by water.