A guy visiting the chemistry department cafeteria, hears the woman in from of him ask for a "glass of H₂O"

So he says "I'd like a glass of H₂O too."

And dies.

Hydrogen peroxide is interesting.

It's used for everything from rocket fuel to Elephant's toothpaste.

But the stuff you get at the store is really dilute; 3% H₂O₂ in 97% water. This is because the sell it as a disinfectant, and that's plenty strong to kill most single celled organisms. It doesn't need to be any stronger, and it's pretty reactive as is so it's safer (and cheaper) to not sell it more concentrated than it needs to be.

But for elephant's tooth paste (we are not going to try to make rocket fuel–liquid fuels are way more complicated and dangerous to work with at our scale, even if they are probably safer when you get up to orbital rockets) it would be nice to have it a little more concentrated, say 30%.

But how? We talked about a couple of ideas:

• If the boiling point is different than the boiling point of water we could try distilling it. But someone thought that it would break down before it boiled. Research this
• If it freezes at a different temperature you might be able to separate them that way (some of us were in a chemistry club that got that to work (some) to concentrate acetic acid from vinegar,
• Somebody on the internet says you can separate the water from the H₂O₂ by adding salt (which dissolves in water but ?not? in H₂O₂?). This seems sort of reasonable (other reaction products can be separated this way) but, on the other hand sodium chloride (NaCl) is pretty similar to the potassium iodide (KI) that's used as the catalyst in a lot of elephant's toothpaste demos. So we were dubious.

What do you do in a case like this? You test it!

We first tried adding a surplus of table salt to a small amount of 3% hydrogen peroxide. Nothing happened.

We then tested the peroxide with a little damp yeast and on a scrape, and it fizzed like it should. So at least the argument that it would cause a breakdown was wrong. But had it caused the formation of two layers (one with water, salt, and a little H₂O₂ and another with mostly H₂O₂)? We couldn't tell.