SPOILER ALERT
In switching the television on prematurely to watch the 10pm news bulletin on the first Tuesday evening of September, I accidentally caught a glimpse of a BBC drama called Doctor Foster. I'm sure it's all very entertaining for those who like that kind of thing, the plot for series/season one seems to revolve around the emotional crises facing a family general practitioner who discovers that her husband has been having an extramarital affair with the daughter of one of her patients. Presumably, it is named for the English nursery rhyme about an itinerant doctor who rhymingly goes to Gloucester during inclement weather and succumbs to the precipitation in the most unfortunate manner, which then deters him from ever repeating his visit to that city. Anyway, the scene from the TV drama that I saw showed the eponymous GP extracting two large bottles, one plastic and colorless and one glass and brown from a paper bag she had apparently acquired from the "pharmacy".
The colorless plastic bottle purportedly contained concentrated nitric acid and was labeled with the formula NHO2, which, if it were written correctly HNO2, would be nitrous, not nitric acid. A much weaker acid than nitric. She poured a little of the other unknown liquid from the brown bottle into a glass vase and then added the purported nitric acid. Meanwhile, we see her take a decorated wooden trinket box and pluck what we assume is her gold wedding band from the box. She then heads for the garden with the acidic mixture and with much dramatic effect and many a pause, gently drops the wedding ring into the mixture and gives it a quick stir with a stainless steel teaspoon. After a rather short time the ring, we see, has completely dissolved.
Health and safety and acid handling protection aside, I assume that what she was supposed to be making aqua regia. That mixture is usually one part concentrated nitric acid to three parts concentrated hydrochloric acid. This is a heady brew that does indeed dissolve gold. But, that mixture is a clear yellow, and sometimes fuming, liquid. I don't think we ever clearly see the label on the brown bottle. I did a screen grab of the dimly lit, slow-motion scene from the show and a "boost and enhance" in my photo editor. It looks like it is labeled "Hydrochloric acid", although not concentrated and below that something illegible that may or may not end in acid. Meanwhile, twice we are treated to the NHO2 label on the colorless plastic bottle though. However, if I recall from my days in the lab, it would be the nitric acid that would be stored in a brown glass bottle and hydrochloric acid in a colorless bottle.
She could have instead used concentrated hydrofluoric acid, but that is even more hazardous to handle. You certainly would not want to get hold of a bottle of concentrated hydrofluoric acid without proper protection and, a fume cupboard with regulatory-compliant scrubbers and filters. Of course, concentrated hydrofluoric acid also dissolves glass (it is used to etch glass, after all) and so you would not want to pour it into your best crystal vase...
Were the BBC simply obfuscating the real recipe for aqua regia, also known as Royal, or King's water (literally) or "Tsar's vodka" (colloquially, in Russia). Perhaps they imagine that viewers do not have access to books or more poignantly, the internet, where they would very quickly find recipes for liquids that dissolve all manner of metals, including gold. As such, it is used to make the electrolyte chloroauric acid for the Wohlwill process for refining gold to 99.999%; which is way beyond 24 carat. Intriguingly, while aqua regia does dissolve gold, platinum, mercury, and other metals it does not dissolve silver, nor iridium.
I know readers will be thinking that I am a pedantic chemist. This is TV drama, we ought to allow them some poetic license in the science, others shows such as the infamous and chemically rich Breaking Bad, feature a lot of accurate science and some poetically extrapolated chemistry. But, I suggest that no dramatic script would erroneously refer to a Shakespearean character and get the name wrong or confuse Ophelia with Othello, so why is scientific accuracy, particularly in a drama hooked on medicine lost? Various reviews of the show tell of the eponymous Doctor Foster dissolving her wedding ring in "bleach". It so obviously is not meant to simply be bleach, the script does, I think, purport to her using aqua regia albeit with some obvious scientific inaccuracies for whatever reason. The ingredients of that mixture are available, but probably not from a GP's pharmacy despite the fact that we British usually refer to a pharmacy as a "chemist's shop".
Meanwhile, apologies for this minor spoiler for fans of the show, you will have to wait for the second episode to discover her intentions for the hypodermic syringes and sealed vials of unknown liquids the good doctor puts in her medicine bag.
David Bradley blogs at Sciencebase Science Blog and tweets @sciencebase, he is author of the popular science book "Deceived Wisdom".