Which is the correct name for P4O10

Which is the correct name for P4O10? A. phosphorus oxide B. phosphorous decoxide C. tetraphosphorus decoxide D. tetraphosphorus oxide E. decoxygen tetraphosphide

The Correct Answer and Explanation is:

The correct name for P₄O₁₀ is:

C. tetraphosphorus decoxide

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Explanation

P₄O₁₀ is a binary covalent compound, meaning it is composed of two nonmetals—phosphorus (P) and oxygen (O). The naming of such compounds follows specific rules based on the IUPAC (International Union of Pure and Applied Chemistry) nomenclature system.

Step-by-Step Naming:

1. Identify the elements:
   • Phosphorus (P)
   • Oxygen (O)
2. Use prefixes to indicate the number of atoms:
   • 4 phosphorus atoms = tetraphosphorus
   • 10 oxygen atoms = decoxide
   Prefixes:
   • 1 = mono-
   • 2 = di-
   • 3 = tri-
   • 4 = tetra-
   • 5 = penta-
   • 6 = hexa-
   • 7 = hepta-
   • 8 = octa-
   • 9 = nona-
   • 10 = deca-
   Note: When “deca-” is combined with “oxide,” the “a” is usually dropped to avoid awkward pronunciation: deca + oxide → decoxide
3. Combine the names:
   • The compound becomes tetraphosphorus decoxide

Why Not the Other Options?

• A. phosphorus oxide – Too vague; doesn’t indicate the number of atoms.
• B. phosphorous decoxide – “Phosphorous” is the adjective form used in compounds with phosphorus in a lower oxidation state (like phosphorous acid), but it’s not correct in this covalent context.
• D. tetraphosphorus oxide – Incomplete; doesn’t indicate 10 oxygen atoms.
• E. decoxygen – Not a valid compound name; oxygen doesn’t form “decoxygen” compounds.

Common Use:

P₄O₁₀ is commonly known as phosphorus pentoxide in industry, reflecting its empirical formula (P₂O₅), but the molecular name tetraphosphorus decoxide is the correct systematic IUPAC name based on its actual molecular composition.