Phosphoric acid whose formula H3PO4, also called phosphoric.This compound under normal conditions is a solid state of aggregation.Small crystals of the substance is colorless.Acid is readily soluble in water, ethanol and other organic solvents.In the solid and liquid state the molecules of the substance due to the association of hydrogen bonds, which is why concentrated H3PO4 has increased viscosity.The boiling point of 42.3 C, while heating to 213 C passes into pyrophosphoric acid H4P2O7.
Phosphoric acid is an electrolyte medium strength as well as tribasic acid, it dissociates in aqueous solutions stepwise in three stages.
Get phosphoric acid from its salts are usually contained in the phosphate minerals - apatite and phosphorite, under the influence of sulfuric acid.Also by hydration of phosphorus oxide (V) by hydrolysis or an inorganic compound - phosphor pentachloride.
Phosphoric acid reacts with bases, metal oxides, salts, active metals and strong acids.The interaction with hydroxides neutralization reaction occurs, the result is the formation of salt and water.Reacts with metal oxides also form salt and water.When reacting with the salts exchange reaction occurs in which the new salt is obtained and the acid.The reaction of orthophosphoric acid with silver nitrate (salt) is a qualitative reaction, allowing it to detect its solutions.The result - a yellow precipitate falls - silver phosphate (Ag3PO4).With active metals, which are among the Beketov to hydrogen reacts replacement.Working with strong acids (chlorine), shows the dual nature (amphoteric) and forms a complex salt - phosphoryl.Also this connection can be thermally decomposed to pyrophosphoric acid.
Phosphoric acid, the use of which is widely, widely used in many industries.For example, in agriculture, in particular in the production of fertilizers containing phosphorus.Such fertilizers can improve not only productivity, but also positively influence the microbial composition of the soil, contributing to the development and proliferation of beneficial bacteria, as well as to increase the hardiness of crops.In the food industry the acid used as a food additive E 338, which is contained in a small amount in the marmalade, syrup and carbonated beverages.It is because of the content of phosphoric acid and citric acid in beverages, in their excessive use is the destruction of tooth.This property soften tooth enamel and dentin has been used by dentists.For example, phosphoric acid containing a special paste, applied to the tooth prior to filling of demineralization and promotes its tissues.The substance is used for etching of wood and create a non-flammable paint products and building materials (non-flammable phosphate foam fosfodrevesnye plate).Widely used in soldering copper, ferrous metals, stainless steel as a cleaner which removes from the surface of different metal oxides.It is also used in the cleaning of the scale, the production of detergents and molecular biology.
Phosphoric acid found such an active and diversified use because of its physical and chemical properties and relatively inexpensive receivable.
