Well, the 25M stuff was for some experiment in organic chemistry. I'm pretty sure that the stuff in the stock bottles is 12M, and if you want any more you have to order it seperately. Basically, there was a tiny little vial of it with an eyedropper in the fume hood. For part of the experiment, you had to add one drop to a test tube. Naturally enough, when I was getting it, I waited until the teacher wasn't looking and then dripped some on some metal. PPPPSSSSSTTT...... the metal dissolved. Wow, cool, I thought. So I kept dripping it on as much metal as I could find... I ended up even taking the zipper pull off my binder so I could melt it. Then I noticed the teacher looking so I figured I had better continue on with the experiment. I picked up the vial so I could aim the eyedropper, and when I was replacing the eyedropper, a bit dripped down the side and onto my hand.
It's a strange thing, being burnt by acid. For a couple of seconds you don't notice anything. Then it feels warm. Then all of a sudden it starts to burn like crazy. Fortunately, as soon as I noticed it on my hand, I made a direct path to the sink and managed to get my hand under the running water just after it started to burn.