Phosphoric acid, with the chemical formula H3PO4, is a white or colorless, odorless, viscous liquid or solid. As a strong acid, phosphoric acid is widely used in industry and daily life. It is the most important compound of phosphorus and is used to produce phosphate salts.
Chemical and Physical Properties of Phosphoric Acid:
- Molecular Weight: 98 g/mol
- Melting Point: 42.35 °C
- Boiling Point: 213 °C
- Density: 1.885 g/mLSolubility: Highly soluble in water and alcohol, low solubility in ether
Production Methods of Phosphoric Acid:
- Sulfuric Acid Method: This is the most common production method for phosphoric acid. Phosphoric acid is obtained by reacting phosphate rocks with sulfuric acid. Calcium sulfate is also produced as a by-product in this process.
- Thermal Method: This is the purest method for producing phosphoric acid. Phosphoric acid is obtained by burning phosphorus in a mixture of air and steam. Phosphorus oxide is also formed as a by-product.
- Lime Method: This is an alternative production method for phosphoric acid. Phosphoric acid is obtained by reacting sodium carbonate solution with lime (calcium hydroxide). Sodium hydroxide is also formed as a by-product.
Applications of Phosphoric Acid:
- Agriculture and Fertilizer Production: Phosphoric acid is used in the agricultural sector for fertilizer production. Phosphorus is an essential nutrient for plant growth and development. By producing phosphorus-containing fertilizers, phosphoric acid helps increase soil fertility.
- Food and Beverage Industry: Phosphoric acid is used as an acidity regulator in food and beverages. It is particularly preferred in soft drinks (cola, fruit juices, carbonated beverages) and processed foods to balance the taste with sweeteners.
- Chemical Industry: Phosphoric acid is used as a catalyst or intermediate in organic synthesis and chemical reactions. It is also used in metal surface anti-rust coatings and paint production.
- Metal Cleaning and Rust Removal: Phosphoric acid is an effective agent for rust removal and metal surface cleaning. When applied to metal surfaces, it helps dissolve rust and provides a clean surface.
- Dentistry and Oral Care Products: Phosphoric acid is used in dentistry and oral care products. It is especially used in bonding procedures to prepare the tooth enamel.
- Water Treatment: Phosphoric acid is used in water treatment processes to adjust phosphate solutions. It is an important chemical for phosphorus control, particularly in wastewater treatment plants.Metal Surface Coatings: Phosphoric acid is one of the main components in anti-corrosion coatings for metal surfaces. It is used to enhance the resistance of metal surfaces against corrosion.