Nitric acid fuming nitric acid at concentrations above 86%. Nitric acid is the primary reagent used for nitration – the addition of a nitro group, typically to an organic molecule. While some resulting nitro compounds are shock- and thermally-sensitive explosives, a few are stable enough to be used in munitions and demolition, while others are still more stable and used as pigments in inks and dyes. Nitric acid is also commonly used as a strong oxidizing agent. Commercially available nitric acid is an azeotrope with water at a concentration of 68% HNO, which is the ordinary concentrated nitric acid of commerce. This
Picric acid crystalline salts of organic bases (picrates) for the purpose of identification and characterization. In metallurgy, a 4% picric acid in ethanol etch called "picral" has been commonly used in optical metallography to reveal prior austenite grain boundaries in ferritic steels. The hazards associated with picric acid has meant it has largely been replaced with other chemical etchants. However, it is still used to etch magnesium alloys, such as AZ31. Bouin solution is a common picric-acid-containing fixative solution used for histology specimens. It improves the staining of acid dyes, but it can also lead to hydrolysis of any DNA in the