Nitric acid
Nitric acid (HNO3) was a highly toxic, highly corrosive acid capable of causing severe burns.

In Seska's rewritten version of the holodeck program Insurrection Alpha in 2373, The Doctor applied 20 ccs of nitric acid to a wound Tom Paris had received, noting it as "a little proverbial salt in the wound." ()

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de:Salpetersäure
Chemical compounds