Question

A flaming fuse box should be sprayed with what type of fire extinguisher?

Answer 1

Well, I would use liquid nitrogen........

Explanation:

Powder, carbon dioxide, or water mist are suitable according to the graph. And note that laboratories will have similar lists taped up to the sides of the lab walls as a statutory requirement.

Mind you, when the $hit hits the fan, and you are actually required to use an extinguisher in earnest you are very unlikely to read the chart properly beforehand. I have seen a few still fires (containing sodium and amalgam) put out with a `CO_2` extinguisher (for which use it is contraindicated). And if it is a bigger fire, often the physical heat of the flame prevents you from approaching it.

As a chemist, it is your responsibility to read the regulations beforehand, and also to PREASSESS the likely hazards and outcomes of a given experiment, and also consider an appropriate response to the fire (which might be to run away and trip the fire alarm). In most chemistry laboratories there will be a dedicated safety officer, and if there is not you need one.