What is Na4P2O5? Important knowledge about Na4P2O5.

1. Definition of Na₄P₂O₅
   Na₄P₂O₅, also known as tetrasodium pyrophosphate or tetrasodium diphosphate, is a chemical compound composed of sodium, phosphorus, and oxygen. In its chemical formula, Na₄P₂O₅, there are 4 atoms of sodium, 2 atoms of phosphorus, and 5 atoms of oxygen. These atoms are combined to form a molecule of Na₄P₂O₅. This compound has a molecular weight of 265.9 g/mol. It consists of ionic structure made up of 4 sodium ions (Na+) and one pyrophosphate ion (P₂O₇₄-).

2. Properties: Na₄P₂O₅
   2.1 Physical properties: Na₄P₂O₅ is a white, odorless solid with a pH of about 10 when dissolved in water.
   2.2 Chemical properties: Na₄P₂O₅ can act as a complexing agent, capable of reacting with metal ions to form complex compounds.

3. Common chemical equation:
   Na₄P₂O₅ is often used in the preparation of phosphorus compounds. For example, it can react with hydrochloric acid to produce H₃PO₄:

Na₄P₂O₅ + 7HCl -> 2H₃PO₄ + 4NaCl

4. Preparation of Na₄P₂O₅
   4.1 Laboratory preparation: Na₄P₂O₅ is usually prepared through the reaction between sodium phosphate and sodium hydroxide:
   Na₃PO₄ + NaOH -> Na₄P₂O₅ + H₂O
   4.2 Industrial preparation: In industry, Na₄P₂O₅ is typically produced through the reaction of sodium bicarbonate with tetraphosphorus decoxide:
   10 NaHCO₃ + P₄O₁₀ -> 4Na₄P₂O₅ + 10CO₂ + 5H₂O