What happens during vigorous chemical reactions?
Everyone has probably seen this during a chemistry lesson demonstration in school. The teacher takes either sodium or potassium metal and throws it in a beaker of water. The alkali metal reacts so quickly it causes an explosion. This was always thought to be the result of the sodium or potassium dissolving quickly and generating steam and so much heat that the hydrogen gas that's formed from the reaction is ignited. This has been proven to be wrong. Steam would keep the metal from reacting by forming a shield on the water. The real reason this reaction causes an explosion is because the alkali metal forms spikes down into the water that rapidly generate positively charged alkali metal ions, which repel and cause a Coulomb explosion. That's why the reaction proceeds so quickly. This was discovered at the University of Southern California by using high-speed photography.
The most vigorous chemical reactions occur between the metals in the first column of the periodic table and the elements in the last column. In other words the most explosive reactions are between the alkali metals and the halogens, such as reacting sodium with fluorine. Reactions like this are impractical because neither element is natural and must be produced or refined.
I remember a chemistry lab session where making oxygen was the experiment for the day. Heating a mixture of potassium perchlorate and manganese dioxide in a glass tube with a Bunsen burner produces oxygen gas. This oxygen gas was then allowed to react with magnesium, carbon powder and other things to show how energetic oxidation can occur. It turns out both carbon and manganese dioxide are black powders. Well, a student mixed carbon with potassium perchlorate by mistake and created a bomb. The test tube exploded and imbedded into his arm and had to be removed surgically. Yikes! The instructor wanted to pull the test tube out, but I reminded him that to do so could allow excessive bleeding if the tube had punctured an artery. Fortunately, the instructor listened and waited for the medics.
Another very energetic reaction is obtained by mixing potassium permanganate and hydrogen peroxide. This also creates oxygen and a lot of steam.
Another somewhat dangerous reaction is obtained by mixing Iodine crystals with ammonium hydroxide to make nitrogen triiodide. When this stuff dries, it detonates at the least provocation like brushing it with a feather; obviously this is very impractical idea!
A lot of otherwise normal chemical reactions can get out of hand and cause a fire or explosion. I've seen a simple etching reaction (chemical milling of copper to form a circuit board) using ammonium persulfate, a very strong oxidizing chemical. If done too quickly and without adequate cooling this reaction can take off and cause an explosion.
Oxygen can cause unwanted reactions in situations where it isn't supposed to be involved. I'm sure you've heard of explosions in flower grinding plants and even in places where sawdust is created. Given the right conditions--fine particle size and cloud generation) the flour or dust can explode, which is actually a rapid oxidation reaction.
The main thing to keep in mind is that some chemical reactions can produce exorbitant amounts of heat, which under the right conditions, could explode. So, be careful.
Thanks for reading.