Nitric acid

Nitric acid (HNO₃) is a colourless to yellow liquid with a pungent odour, known for its strong oxidising properties. It is a key industrial chemical, with applications spanning agriculture, pharmaceuticals, and electronics. In laboratories, it is used for sample digestion, cleaning glassware, and as a reagent in organic synthesis.

What are the primary industrial uses of nitric acid?

The largest application of nitric acid is in the production of ammonium nitrate fertilisers, which are essential for modern agriculture. It is also used in the manufacture of explosives such as nitroglycerin and TNT. In the chemical industry, nitric acid serves as a nitrating agent for producing nitro compounds used in dyes, pharmaceuticals, and polymers. Additionally, it plays a role in metal refining and semiconductor manufacturing, where it helps remove impurities through passivation or etching.

How should nitric acid be handled and stored safely?

Due to its corrosive and oxidising nature, nitric acid must be handled with appropriate personal protective equipment (PPE), including gloves, goggles, and lab coats. It should be stored in dark glass or polyethylene containers away from organic materials and reducing agents to prevent hazardous reactions. Exposure to light can cause decomposition, producing toxic nitrogen dioxide (NO₂) gas. In case of spills, neutralisation with a base such as sodium bicarbonate is recommended, followed by proper disposal in accordance with local regulations (e.g., REACH, TSCA).

Related concepts

Nitric acid is often used alongside other strong acids such as sulfuric acid (H₂SO₄) and hydrochloric acid (HCl). It is also involved in the production of nitrate salts, which are regulated under environmental and safety frameworks like GHS and ISO standards.