Phosphoric acid, also known as orthophosphoric acid or phosphoric(V) acid, is a mineral (inorganic) acid having the chemical formula H3PO4 and chemical weight *7.*9.
Its executed standardare GB/T********8(TG) and GB********4(FG).
Properity: Colorless. Its melting point is *2.*5 Dgree and when heated to **0 Degree, it becomes Meta Phosphoric Acid. Its relative density is 1.**4. it is easily soluble in water and resolves in ethanal. PA can irritate human skin to cause phlogosis and destory the issue of human body.
Application: 1.Chemical reagent: Phosphoric acid is very commonly used as an aqueous solution of *5% phosphoric acid or H3PO4. Because it is a concentrated acid, an *5% solution can be corrosive, although nontoxic when diluted.
                     2.Rust removal: Phosphoric acid may be used as a "rust converter", by direct application to rusted iron, steel tools, or surfaces. The phosphoric acid converts reddish-brown iron(III) oxide, Fe2O3 (rust) to black ferric phosphate, FePO4.
                    3. Processed food use: Food-grade phosphoric acid (additive E**8) is used to acidify foods and beverages such as various colas, but not without controversy regarding its health effects. It provides a tangy or sour taste and, being a mass-produced chemical, is available cheaply and in large quantities
                    4.Medical Use: Phosphoric acid is used in dentistry and orthodontics as an etching solution, to clean and roughen the surfaces of teeth where dental appliances or fillings will be placed. Phosphoric acid is also an ingredient in over-the-counter anti-nausea medications that also contain high levels of sugar(glucose and fructose). This acid is also used in many teeth whiteners to eliminate plaque that may be on the teeth before application.
   We obtain Phosporic Acid by burning elemental phosphorus to produce phosphorus pentoxide and dissolving the product in dilute phosphoric acid. This produces a very pure phosphoric acid, since most impurities present in the rock have been removed when extracting phosphorus from the rock in a furnace. The end result is food-grade, thermal phosphoric acid; however, for critical applications, additional processing to remove arsenic compounds may be needed.