If you're asking what will happen if you put gasoline in a diesel engine, the engine will be destroyed if you run it on gasoline.
Yes
Get the system darined ASAP
no
Don't know how much gasoline was put in or how much diesel was in the tank before gasoline was added but if you didn't run the engine after the gasoline was put in and you drained it, you should be okay.
Gasoline and propain
Sure.
Neither a gasoline or electrical fire should be put out by water. A gasoline fire should be put out by a fire extinguisher labeled A B C. An electrical fire should first have the power switched off. Then the fire extinguisher should be used.
Diesel in a gasoline engine will not harm the engine other than that, depending on how much diesel you put in the tank, it will simply not run. It may clog the fuel filter or injectors but will do no other damage. Drain the tank and fill it up with gasoline if you put in over a couple of gallons.
Unleaded
Petrol is called Gasoline in the USA.
It will ruin the engine. Ethanol is a much harsher fuel than gasoline and also requires a higher compression ratio to burn efficiently.