The most suitable substance for putting out petrol fire is

The most suitable substance for putting out a petrol fire is not water, carbon(IV) oxide, or a fire blanket, but sand. Sand can be used to smother a petrol fire by covering the flames and cutting off the oxygen supply, which will cause the fire to go out. However, it is important to note that sand should only be used on small fires and not on larger fires, as it can be difficult to spread a large amount of sand over the fire and it may not be effective. In such cases, it is best to evacuate the area and call the fire department.