I wonder what the strengths of the solutions are...coke is highly acidic - but it is phosphoric acid (another reason why detail matters....)
That hydrochloric acid is concentrated. It's likely 36%. That container that it is stored in (the little flask looking thing with the ground glass stopper) is the traditional container for highly concentrated acids (sulfuric, nitric, hydrochloric, glacial acetic acid).
When you open up a flask like that of concentrated HCl, it doesn't stay liquid. It will keep fuming and make acrid HCl vapors. You have to work with it in a hood otherwise if you get any inhaled you will be immediately burned/verrry irritated. (Speaking from experience here.)
Phosphoric acid is a weak acid and is present in low amounts in coke. Coke as a pH of about 3.5. That concentrated hydrochloric acid is at a pH of pretty much 0.
I would bet that the NaOH solution is 40% or so. That's pretty much as concentrated as you'll see in labs although sometimes you'll get 45% solutions.
Also, every cool video! Same thing happens with aluminum and iron sulphate (the stuff used to etch copper electronics boards) I've done that in my spare time (used to make etched jewelry). You can do some really cool stuff if you control it. It's a much less violent reaction of course! You definitely want to do it outside though!
I'm wrong! I lied, its probably 36% HCl. I was thinking of nitric acid! So sorry!! My bad. HCl will just be vapor at 70-100%... Oops. I fixed it!!