You are wrong. A high school chem class could bring the different chemical required (when mixed) to bring down a large aircraft. A large explosion is not required if placed in the right location. Probably a couple of large firecrackers could do it. Signed: An aircraft mechanic for 22 years.

Sorry... an aircraft mechanic might know where to place an explosion, and maybe even the actual force needed. But to say a high school chemistry class could do it is reaching a bit outside your expertise. Besides, no airplane has been brought down by loss of cabin pressure alone (unless you count pilots losing consciousness).

I actually work with high explosives from time to time, and routinely interact with folks who do it for a living. The first question they asked was "were they planning to build up fumes then light a match?"

As it turns out, there are much more effective things to do, all of which require less care and more planning than attempting to mix chemicals on a plane. Perhaps my favourite is disabling the smoke detectors in the lavatory. It's a federal offense, you know.