During the course of amateur experimentation, there is always the occasional experiment which has an unexpected problem. Sometimes this is due to poor lab technique and lack of safety precautions, while other times it is one of those one-in-a-thousand coincidences that seem so unreal. In this article I will detail some of my experiences as well as include videos and excerpts of the errors of other amateur scientists. Proper attribution will be given for all work that is not mine.
Hydrogen torch fail: My younger brother occasionally performs chemistry experiments, which do go wrong due to lack of proper planning. In one of these experiments, aluminium foil was placed in muriatic acid in a plastic shampoo bottle. A special nozzle / valve apparatus constructed of spare parts was connected to the modified cap. After the normal waiting time, the reaction began and the small amount of hydrochloric acid in the bottle began heating up as the reaction progressed. Fortunately, he waited a while before igniting the expelled hydrogen, and did not have a gas explosion inside the bottle. However, the bottle was not designed for the kind of heat produced by this reaction, and began to soften and deform in his hands. He panicked and finally decided to drop the bottle in the bathroom sink. He then spilled the hot hydrochloric acid right down the drain, eating the thin chrome plating off the drain plug.
Pyrophoricity: I was exploring battery chemistry and dissecting common household batteries to determine if their contents held any useful chemicals. I opened a nickel-cadmium battery expecting to see a shiny lump of soft cadmium metal in it, but was disappointed. I decided to try opening a similar battery, the nickel metal-hydride battery. Fortunately, I correlated the high power capacity and jelly-roll construction of the NiMH battery with highly reactive chemicals, and placed all of the components on a metal surface. Sure enough, a minute later I come back and the electrolyte paper is flaming. I beat out the small flames with another metal object and tell my younger brother about it. He decides to open a NiMH battery and see whether it could really catch on fire. He dissects it over a metal dish but unwittingly (as I was videotaping) dumped some powder from the battery into his garbage can, which was full of flammables. Half a minute later he smelled smoke coming from under his table and looked down to see a garbage can full of burning tissues. I tell him to take it to the bathroom sink, where he quenches the flames with water. I do not need to tell you what would happen if these chemicals got casually dumped in the trash.
Tert-Butyllithium fire death: A researcher at the University of California, Los Angeles, was removing tert-butyllithium from a bottle into a syringe when the syringe fell apart and the dangerous chemical became exposed to air. It instantly ignited (due to moisture in the air), causing burns that caused her death. Link_to_article
Sciencemadness member death: User myfanwy94, it appears, passed away a couple of years ago shortly after announcing that he was going to synthesize phosgene. This is not proven, but this link will show the thread on sciencemadness.org about his disappearance. By the way, here is an example of his careless experimentation, this time with sodium metal.
Bottle bomb explosion: Shaking is often not necessary. Holding these dangerous items for too long is the primary reason for premature explosions.
Bottle bombs are notoriously unpredictable, and are made with some nasty chemicals. A toilet bowl cleaner bomb, for instance, will splatter you with boiling hot acid, whereas a chlorine bomb produces toxic gases. Never use these as a prank because of this.
Periodic videos: Chromium trioxide reacts with alcohol, causing a violent flaming reaction. The Professor forgets to shut off the smoke detectors, and there is a problem. Even professional chemists make mistakes sometimes.
Chlorine accident: I mixed manganese dioxide from alkaline batteries with muriatic acid in a small container and left it in an unventilated room. When my mother unwittingly walked into the room 20 minutes later she was not happy with the smell. Of course, there was splatter all over the nice white surface I placed the container on as well. No one was harmed as the chlorine concentration was not dangerously high.
Gasoline has a high vapor pressure, which means it evaporates swiftly. The vapor flows along the ground for quite a distance, mixing with the air to form a highly-flammable air zone. Any spark or flame in that zone causes an instant flare-up. This is why gasoline should not be used to start fires.