The process of Making Phosphoric Acid & It's Facts - WorldOfChemicals

Few things you should know about Phosphoric acid

Category : General Chemicals
Published by : Data Research Analyst,

Phosphoric acid which is also known as Orthophosphoric acid, which is the IUPAC name of phosphoric acid is an inorganic acid with a chemical formula of H3PO4. Phosphoric acid is one of the very important and usable mineral acids. Phosphoric acid has a crystal structure as a monoclinic and molecular shape of pseudo-tetrahedral.

Properties and Facts about Phosphoric Acid

  1. It is a non-volatile, white crystalline solid in its purest form and in manufactures through phosphate rock treatment.

  2. Phosphoric acid is a non-toxic odorless acid with the Boiling point of 158 degree Celsius and a melting point of 42.35 degree Celsius.

  3. It is colorless, viscous liquid when less concentrated with the density of 1.885 g/mL.

  4. Phosphoric acid reacts in a different way from other mineral acids as it has 3 H-atoms which are replaceable and acidic.

  5. It can form three different classes of salts by reacting with bases.

  6. It is soluble in water and alcohol and the most common sources of it are an 85% aqueous solution.

Preparation of Phosphoric Acid

In Industry Phosphoric acid is produced by two general processes: Thermal process and Wet process.

Wet Process:

This process is majorly used in the commercial industry. Phosphoric acid is prepared by combining sulphuric acid with tricalcium phosphate rock. The reaction of this process is:

Ca5 (PO4)3X + 5?H2SO4 + 10?H2O → 3?H3PO4 + 5?CaSO4•2?H2O + HX

Where, x may constitute OH, F, Cl, and Br.

Thermal Process

The thermal process is the expensive process which produces pure phosphoric acid and is used in the food industry. In this process, elemental phosphorous is burnt which produces phosphorus pentoxide which is then dissolved in diluted phosphoric acid. This process produces very pure phosphoric acid as large impurities get removed while extracting phosphorus in a furnace from the rock.


• Phosphoric acid is mainly used as Fertilizers, consuming around 90% of its production.

• It is used as a food additive in various soft drinks and jams. It is also used as leavening agents.

• Rust removal: Phosphoric acid can be used to remove rust by directly applying it to rusted iron, steel or other surfaces.

• In medicines: It is used as an etching solution in dentistry and orthodontics for cleaning and roughens surfaces of teeth. It is also used in many teeth whiteners.

• Other uses: Phosphoric acid is used as an electrolyte, pH modifier, dispersing agent, sanitizing agent and as a household cleaning agent.

Why soft drinks constitute phosphoric acid?

Food-grade phosphoric acid is available widely and is cheap to obtain so Soft drinks companies use it to give a different particular flavor. Phosphoric acid is used in soft drinks to give it a tangy taste and it also acts as a preservative in soft drinks and other similar food products.

Hazards and Safety


• Phosphoric acid is not a hazardous or toxic compound. It is safe for skin and for consumption also in small concentrations.

• But when it comes in contact with skin or consumed in high concentrations it becomes corrosive and can result in burns.

• There is a high risk of fire or explosion when strong oxidizers are added to the phosphoric acid.



• Handling: While handling phosphoric acid following equipment are recommended: For eye protection: Safety Goggles, skin protection: Gloves, body protection: chemical protective suit, respiratory protection: air-purifying respirators.

• Storage: It should be stored in corrosion-resistant containers. Containers should be kept upright to prevent leakage. uses cookies to ensure that we give you the best experience on our website. By using this site, you agree to our Privacy Policy and our Terms of Use. X