Wounded iron nail
As I mentioned before, the iron (III) thiocyanate can be used to simulate blood and can give a nice illusion of cutting flesh. Thus also known as “scenic blood”. But let’s do something more sophisticated. Let’s make iron bleed!
You see an iron nail hanging in a solution of potassium thiocyanate (about 1 g per 80 ml water). Once hydrochloric acid and hydrogen peroxide are added, the nail begins to bleed. I used 1 ml 30% of hydrochloric acid and several drops of 35% hydrogen peroxide. The latter one is hard to find, so it’s also possible to add 3% available via a drugstore. Just need 1-2 ml.
What is going on?
1. Iron reacts with hydrochloric acid and forms iron chloride. Same as here. The hydrogen bubbles are easy to see.
Fe (s) + 2HCl (aq) → FeCl2 (aq) + H2 (g)
2. Hydrogen peroxide oxidizes iron (II) to iron (III).
2FeCl2 + H2O2 + 2HCl → 2FeCl3 + 2H2O
3. Iron (III) forms a red colored substance with thiocyanate as I explained before.
It’s funny to notice that there is no red color appearing around the paperclip. Probably it doesn’t contain iron at all or is from iron, but covered with a layer of another metal for protection (in this case it should bleed later).
And here is a “romantic” version of the same experiment called “Bleeding Heart” by TwirlyWhirly: