Phosphoric acid, also called phosphoric acid, is a chemical compound whose formula is H 3 PO 4 . The article gives the density of phosphoric acid, and discusses its basic physical and chemical properties.
Chemical properties
Phosphoric acid has the chemical formula H 3 PO 4 , that is, its molecule consists of 3 hydrogen atoms, 4 oxygen atoms and 1 phosphorus atom.
When asked the question, phosphoric acid - which in terms of chemical activity, it should be said that it is much weaker than sulfuric or hydrochloric. This property is used to produce phosphoric acid from rocks containing calcium phosphate. These rocks are dissolved in sulfuric acid, resulting in the following chemical reaction: Ca 3 (PO 4 ) 2 + H 2 SO 4 ==> CaSO 4 + H 3 PO 4 . After a chemical reaction, the solid calcium sulfate (CaSO 4 ) is filtered off, and the remaining liquid is pure phosphoric acid.
The anion of this acid is called the phosphate ion (PO 4 ) 3- . This anion plays an important biological role because it is involved in the formation of DNA and RNA.
Physical properties
The considered acid under normal conditions can have either a liquid or solid consistency. In the solid state, it is a transparent crystal with an orthorhombic lattice. The density of orthophosphoric acid in the solid state is 1892 kg / m 3 . Note that the crystals of this acid have hygroscopic properties.
Phosphoric acid in the liquid state is transparent and has a slightly yellowish tint. The density of orthophosphoric acid in the form of a liquid is 1841 kg / m 3 , that is, its crystals are more dense. Since the given density value is larger than the value of this value for water, a decrease in the acid concentration will lead to a decrease in the density of the solution. So, the density of orthophosphoric acid in its aqueous solution with a concentration of 85% (it is at such a concentration that it is commercially available) is 1685 kg / m 3 , and for a concentration of 50% its value drops to 1334 kg / m 3 . All values shown are 25 ºC.
Phosphoric acid is a non-combustible substance that dissolves well in water, its crystals melt at a temperature of 42.2ºC. Saturated vapors of phosphoric acid have a density 3.4 times greater than the density of air.
Use of phosphoric acid
The chemical formula of orthophosphoric acid (H 3 PO 4 ), which fully characterizes its chemical properties, determines the use of this substance in a number of areas of human activity:
- additive to carbonated drinks (international marking E-338);
- an important element in the process of restoration of tooth enamel (acid improves the adhesive properties of enamel);
- an important component in water softeners and dishwashers;
- in laboratory conditions it is often used to adjust the pH of solutions;
- It finds application in the manufacture of asphalt.
Despite its weak acid properties, phosphoric acid can still be harmful to human health, therefore, when working with it, you must follow the safety precautions.