Nitric Acid is a colorless or yellow liquid with a characteristically pungent odor, corrosive and oxidizing properties. It is a strong acid with the Chemical formula HNO3. It is also known by many synonyms such as Spirit of Nitre and Aqua fortis.

Obtained through oxidation of ammonia under presence of a catalyst, it is a transparent liquid in its pure form but turns to yellowing colour as it turns old. This colour appears as a result of the decomposition of Pure nitric acid into Nitrogen oxides and water.