Final answer:
The correct formula for tetraphosphorus decaoxide is P4O10, also known as phosphorus(V) oxide, which reacts with water to form orthophosphoric acid.
Step-by-step explanation:
The correct formula for tetraphosphorus decaoxide is P4O10. This compound is also known as phosphorus(V) oxide and is a white powder that exhibits significant stability. When P4O10 is dropped into water, it reacts to form orthophosphoric acid according to the following reaction:
P4O10(s) + 6H₂O(l) → 4H3PO4 (aq)
Phosphorus also forms another oxide known as phosphorus(III) oxide or tetraphosphorus hexaoxide, P4O6, which is a different compound.