PeriodicExperiments: #7: Pepto-Bismuth

I was in the pharmacy the other day when I saw something neat that I didn't think still existed: Pepto-Bismol. For those who don't know, Pepto-Bismol is a digestive medicine that has been around for quite a long time. The reason I was interested in it was not because I had a terrible stomach ache, but because of the drug's chemical makeup. I had heard a while back that the medicine contained bismuth as part of its active ingredient bismuth subsalicylate (C7H5BiO4). Bismuth is a non-toxic heavy metal that resembles lead in a lot of ways. If you saw my first post about diamagnetic levitation, you'll also know that it weakly repels strong magnets. Anyway, I decided to buy a small pack of Pepto-Bismol tablets with the hope of somehow extracting bismuth from them. After going online and finding the correct procedure, I learned that my hope could easily become a reality.

I started by crushing up the majority of the bright pink tablets in my mortar and pestle. I then placed the neon powder in a beaker and added some diluted hydrochloric acid (HCl). It took a while, but I eventually dissolved the Pepto-Bismol into the hydrochloric acid with a good amount of stirring. After filtering out any leftover solids, I placed a strip of aluminum into the pale pink solution and let it sit for a while. What happened was that the chlorine ions from the HCl let go of the bismuth ions and bonded with the aluminum ones instead. This left the bismuth to simply clump together and form a gray precipitate. I was then able to collect these bismuth particles using a coffee filter. After allowing the powder to dry and putting it into a steel ladle, I attempted to melt it over our stovetop.

Sadly, I never got the shiny silver liquid that I was looking for. Instead the dark dust simply fused together and turned mustard yellow. After thinking about it, I would say that there were most likely too many impurities. As far as the yellow color goes, I suspect that this was due to the oxidation of either the bismuth or the leftover aluminum. I may never know.