Very interesting, thank you for the answer.
I love how diverse HN can be. From Ph.Ds in computer science to former jewelers, there seems to be a little bit of everything.
Follow up question: would the gas have stuck around until the Nazis arrived a while (hours or less?) later? Or would their ventilation have dispersed it enough?
I remember in the science classes I took in HS the ventilation hoods pretty much removed most of the fumes, but we also never worked with anything that was particularly... pungent? My last science class was probably 5 years ago, so that's my level of understanding.
Fume cupboards work pretty well. If you leave the fan running I think all the airflow is in and up the chimney. I presume Bohr would have used one.
(Just got side tracked reading about old style fume cupboards http://www.cf.ac.uk/estat/sustainability/initiatives/ )
I would imagine that anyone who just happens to have some nitric acid (or any strong acid of appreciable quantity and concentration) lying around would have the sense to at least Google the products of the reaction, if they didn't know offhand. Other than that, gold doesn't react with terribly much anyway, does it?
The gas given off is Nitric Oxide (which combines with Oxygen in the air to create Nitrogen Dioxide) and Chlorine and even a small dose can cause serious damage to your lungs if not be fatal.