What is the correct name for the molecular compound with the formula As2O5?

• A. diarsenic pentoxide
• B. diarsenic pentaoxide
• C. arsenic(V) oxide
• D. arsenic pentoxide

Answer: (A)

Verified step by step guidance

1. Identify that the compound As2O5 is a molecular (covalent) compound composed of nonmetals arsenic (As) and oxygen (O).
2. Recall the naming rules for molecular compounds: use prefixes to indicate the number of atoms of each element (di-, tri-, tetra-, penta-, etc.) and name the second element with an '-ide' suffix.
3. Determine the number of atoms of each element in the formula: 2 arsenic atoms and 5 oxygen atoms.
4. Apply the appropriate prefixes: 'di-' for 2 arsenic atoms and 'penta-' for 5 oxygen atoms, and name oxygen as 'oxide'.
5. Combine the parts to form the name: 'diarsenic pentoxide'. Note that 'pentaoxide' is incorrect because the 'a' is dropped before 'oxide' for easier pronunciation.