Nitric acid gold purity. Being a powerful oxidizing agent, nitric acid reacts violently with many non-metallic compounds, and the reactions may be explosive. Depending on the acid concentration, temperature and the reducing agent involved, the end products can be variable. Reaction takes place with all metals except the noble metals series and certain alloys. As a general rule, oxidizing reactions occur primarily with the concentrated acid, favoring the formation of nitrogen dioxide (NO). However, the powerful oxidizing properties of nitric acid are thermodynamic in nature, but sometimes its oxidation reactions are rather kinetically non-favored. The presence of small amounts of nitrous acid
Simultaneously extracted metals and Acid-volatile sulfide the amount of HS produced by the reaction can be calculated. A few important things should be noted about this reaction: Once the quantity (in moles) of AVS has been determined in this way, it is divided by the dry mass of the sediment to obtain the AVS concentration. In addition to the gravimetric method described here, other methods, such as colorimetry, may be used. As noted above, treating metals-containing sediments with HCl liberates metal ions into the acid solution that were previously bound up with AVS. After treatment these are present in solution, along with any metals that were