Final answer:
White phosphorus reacts with oxygen in a combustion reaction to form phosphorus oxides such as phosphorus(V) oxide (P4O10), which in turn can react with water to produce orthophosphoric acid (H3PO4).
Step-by-step explanation:
Reaction Between White Phosphorus and Oxygen
When white phosphorus reacts with oxygen, it undergoes combustion to form phosphorus oxides. One of the reactions that can take place is the burning of phosphorus in excess oxygen to produce phosphorus(V) oxide, also known as tetraphosphorus decaoxide (P4O10). This is an exothermic reaction and the enthalpy of formation of P4O10 is extremely high, indicating that a lot of energy is released during the formation of this compound from its elements. The equation for this reaction is:
4P(s) + 5O2(g) → P4O10(s)
Phosphorus(V) oxide is a white powder and is quite stable. It is a poor oxidizing agent but can react swiftly with water to form orthophosphoric acid (H3PO4), making a hissing sound and releasing heat in the process:
P4O10(s) + 6H2O(l) → 4H3PO4 (aq)
The other product mentioned, phosphorus(III) oxide or tetraphosphorus hexaoxide (P4O6), forms when the reaction involves less oxygen. It can also oxidize further to form P4O10. Both oxides have their importance in producing different compounds, including acids like phosphorous acid and orthophosphoric acid, when they react with water.