Nitric acid is a strong, highly corrosive mineral acid with the chemical formula HNO3. It is a colourless liquid that is soluble in water and can release nitrogen oxides when heated. Nitric acid is widely used in the manufacture of fertilizers, dyes, explosives, and other chemicals, as well as in the etching of metals and the purification of metals e.g Gold & silver It is also used in laboratory settings as a reagent for various chemical reactions.