Phosphoric acid

Absorption

Ortho phosphate is absorbed from, and to a limited extent secreted into, the gastrointestinal tract.

Description

The most common form of phosphoric acid (H3PO4) is the 85% aqueous form. Pure anhydrous phosphoric acid is a white solid with a melting point of 42 C. Phosphoric acid has three pKa values covering a wide range (pKa's: 2.15, 7.20, 12.32). This is the reason why phosphoric acid solutions make a great choice as a buffer.

Chemical properties

Phosphoric acid can appear as a colorless, odorless crystalline solid or a thick, syrupy liquid, with its physical state varying based on its strength and temperature. When concentrated, it is a colorless, odorless, syrupy liquid that, when diluted appropriately, has a pleasantly acidic taste. Pure phosphoric acid, also referred to as orthophosphoric acid, is a clear, colorless mineral acid of moderate strength. It is typically sold as an aqueous solution containing 75%-85% phosphoric acid, in which form it is a clear, viscous liquid.

Pharmacokinetics

Transport of phosphate from the gut lumen is an active, energy-dependent process that is modified by several factors. ... Vitamin D stimulates phosphate absorption, an effect reported to precede its action on calcium ion transport.

The Uses of Phosphoric acid

Phosphoric acid has a wide range of applications across various industries. It is used in the production of superphosphate fertilizers, livestock feeds, phosphate salts, polyphosphates, soaps, waxes, polishes, and detergents. Additionally, it serves as a soil stabilizer, in the manufacture of fire control agents, opal glasses, electric lights, and in processes such as cotton dyeing, tile cleaning, ceramic binding, dental cement, water treatment, electro-polishing, lithography, photoengraving, and process engraving. It is also utilized as a petrol additive, in coagulating rubber latex, and in metal rust proofing before painting. In chemical manufacturing, phosphoric acid acts as an acid catalyst for making ethylene and purifying hydrogen peroxide, as well as in the production of chemicals like ethylbenzene, propylene, and cumene. It is used as a bonding agent for refractory bricks, in extracting penicillin, and as an analytical agent. In the food industry, it functions as an antioxidant, a flavor additive for sharp taste in foods like jellies and soft drinks (e.g., Coca-Cola), and in the manufacture of yeasts and gelatin. Phosphoric acid is also used to manufacture phosphoric acid electrolyte fuel cell systems and has been applied in the treatment of lead poisoning.