Caustic soda?
http://yuanlongchem.com/
Not really explosive.
It is a great cleaning, but it can do some rather interesting things. If you get it on aluminum, it will etch it and make hydrogen gas.
The processes to produce it are pretty varied, but the most common is electrolysis. So you make hydrochloric acid (HCl) and sodium hydroxide (NaCl) from brine (NaCl and water).
Lots of things that can make hydrogen and go boom there.