A11 Reactions of Red and White Phosphorus with Air

Description
White phosphorus ignites spontaneously on a filter paper. Red phosphorus must be ignited with a hot glass rod. White phosphorus reacts faster because it is made up of discrete molecules of four atoms in contrast to red phosphorus, which is a polymeric form of phosphorus with a large average molecular weight.

Equation
P₄(white) + 5O₂--> P₄O₁₀

4 P (red) + 5O₂--> P₄O₁₀

Reference
B. Z. Shakhashiri, "Chemical Demonstrations", Vol. 1, The University of Wisconsin Press, Madison ,Wisconsin, (1983) p.75.