Nitric acid is a kind of strong oxidizing, corrosive acid, belongs to the single inorganic strong acid, is one of the six inorganic strong acids, is also an important chemical raw material. In industry can be used to make chemical fertilizer, pesticides, explosives, dyes, pigments, salts and so on.

Pure nitric acid solute is colorless, but older samples tend to obtain yellow castings due to its decomposition into nitrogen oxides and water. Most commercially available nitric acid has a concentration of 68% in water. When the solution contains more than 86% HNO3, it is called fuming nitric acid. Depending on the amount of nitrogen dioxide present, fuming nitric acid is further characterized as white fuming nitric acid at concentrations higher than 95%, or red fuming nitric acid at concentrations higher than 86%. The anhydride of nitric acid is nitrous pentoxide.