What is the chemical equation for diphosphorus trioxide + water – – – > phosphorous acid ?
The correct answer and explanation is:
Correct Chemical Equation:
P2O3+3H2O→2H3PO3\text{P}_2\text{O}_3 + 3\text{H}_2\text{O} \rightarrow 2\text{H}_3\text{PO}_3
Explanation (300 words):
The chemical reaction between diphosphorus trioxide and water produces phosphorous acid. Diphosphorus trioxide, represented by the formula P₂O₃, is an acidic oxide of phosphorus. It reacts with water in a typical acid-base reaction that forms an oxyacid, specifically phosphorous acid (H₃PO₃).
Phosphorous acid is a weak, dibasic acid containing phosphorus in the +3 oxidation state. When P₂O₃ is dissolved in water, it undergoes hydrolysis, where water molecules break the P–O–P bridges and form hydroxyl groups (–OH) attached to the phosphorus atoms. The balanced chemical equation reflects that one mole of diphosphorus trioxide reacts with three moles of water to yield two moles of phosphorous acid.
This type of reaction is characteristic of non-metal oxides combining with water to form acids. The phosphorus in P₂O₃ has a +3 oxidation state, which is maintained in the resulting H₃PO₃ molecules. Each molecule of phosphorous acid contains one P atom, three H atoms, and three O atoms, two of which are part of hydroxyl groups and one is double-bonded to phosphorus.
The stoichiometry in the equation ensures that all atoms are balanced. Two phosphorus atoms from P₂O₃ produce two molecules of H₃PO₃. The six hydrogen atoms required to form these two acid molecules are provided by three water molecules. Similarly, the oxygen atoms from both the P₂O₃ and H₂O account for the six oxygen atoms present in the two H₃PO₃ molecules.
This reaction is important in inorganic chemistry and is used to understand how non-metal oxides behave in aqueous environments. It also illustrates how acids can form through direct combination of oxides and water, which is significant in both natural and industrial chemical processes.