[Monoamine]

I was distilling some aqueous hydrobromic acid (HBr) and the metal thermometer probe that I had in it dissolved and turned the whole solution dark brown, almost black...  Is this dangerous? Can I fix it somehow?

[Monoamine]

Ok, could this be it?: The iron somehow catalyzed the formation of Br₂? When I took a bit of the dark red/brown/black liquid and added enough sodium thiosulfate (Na₂S₂O₃), it became sort of milky turquoise green, and all the black/red disappeared.

[Monoamine]

Nice... now my whole clothes smell like rotten eggs. Probably nothing to do with hydrogen sulfide... This is why I love chemistry 

[Monoamine]

Okidoki now there's definitely some sulfur depositing in the condenser. Reminds me a bit of yellowstone national park. 

[Orcio_87]

Iron did not catalyze formation of Br₂, as it is reducer not oxidant: Fe + 2 HBr --> FeBr₂ + H₂

Dark brown colour could come from FeBr₃ if HBr was contaminated with Br₂ or FeBr₂ oxidized.

Na₂S₂O₃ reacted with remainder HBr and also reduced FeBr₃ back to FeBr₂:

Na₂S₂O₃ + 2 HBr ---> 2 NaBr + S + SO₂ + H₂O

2 FeBr₃ + 2 Na₂S₂O₃ ---> 2 FeBr₂ + Na₂S₄O₆ + 2 NaBr

Solution was milky green because of presence of Fe²⁺ (green) and coloidal S (white).

Could it be dangerous? Yes - if thermometer was filled with mercury, then the mercury is still there as it will not react with HBr as iron.

[Corribus]

OP identified the thermometer as a metal probe thermometer - which seems to be consistent with what looks to be a probe thermometer in the background of the picture. Unlikely it has anything to do with mercury.

[Monoamine]

Thanks for the reply. Yes it was just a metal probe, not filled with any mercury. Also, I'm still alive