Nitric acid is the inorganic compound with the formula HNO3. It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available nitric acid has a concentration of 68% in water.

The Ricca Chemicals nitric acid can be used to increase the number of acid sites by altering the surface of activated carbon. It is a common laboratory reagent and an important industrial chemical for the manufacture of fertilizers and explosives.