Phosphoric acid, also known as orthophosphoric acid, is a common inorganic acid, a medium-strong acid, with a chemical formula of H3PO4 and a molecular weight of 97.995.
It is not volatile, not easy to decompose, and has almost no oxidation. It has the generality of acid and is a weak ternary acid. Its acidity is weaker than hydrochloric acid, sulfuric acid, and nitric acid, but stronger than acetic acid, boric acid, etc.
Phosphoric acid is easily deliquescent in air. Heating will lose water to get pyrophosphoric acid, and further lose water to get metaphosphoric acid.
Uses of phosphoric acid:
It is mainly used in pharmaceutical, food, fertilizer and other industries, including as antirust agent, food additive, dental and orthopedic, EDIC corrosive, electrolyte, flux, dispersant, industrial corrosive, fertilizer raw material and component of household cleaning products, and also can be used as a chemical reagent.
Agriculture:
H3PO4 is the raw material for the production of important phosphate fertilizers (calcium superphosphate, potassium dihydrogen phosphate, etc.), and also the raw material for the production of feed nutrients (calcium dihydrogen phosphate).
Industry:
Phosphoric acid is an important chemical raw material, the main functions are as follows:
- Treat the metal surface and form an insoluble phosphate film on the metal surface to protect the metal from corrosion.
- Mixed with nitric acid as a chemical polishing agent to improve the smoothness of the metal surface.
- Phosphate esters as raw materials for the production of detergents and insecticides.
- Raw materials for the production of phosphorus-containing flame retardants.
Food:
H3PO4 is one of food additives. It is used as sour agent and yeast nutrient in food, and phosphoric acid is contained in cola. Phosphate is also an important food additive and acts as a nutritional enhancer.
Medicine:
Phosphoric acid can be used to prepare phosphorus-containing drugs, such as sodium glycerophosphate.
