Final answer:
True, phosphorous is never found free in nature because its high reactivity, especially the white allotrope, leads to spontaneous ignition upon contact with air.
Step-by-step explanation:
The statement that phosphorous is never found free in nature is true. Phosphorous is highly reactive and catches fire spontaneously in air due to its reaction with oxygen. White phosphorus in particular is notable for this reaction; it is a toxic, waxy substance that glows and ignites upon contact with air because of its high reactivity with oxygen. To prevent this ignition, it is stored underwater. Red phosphorus, on the other hand, is much less reactive and is used in commercial products like safety matches and fireworks, while black phosphorus is an unreactive crystalline solid.
Phosphorus is never found free in nature. It exists in many allotropic forms, including white phosphorus and red phosphorus. White phosphorus is a toxic, waxy substance that spontaneously ignites in air, while red phosphorus is much less reactive and is used commercially in safety matches, fireworks, and smoke bombs. Therefore, the statement that phosphorus catches fire spontaneously in air by reacting with oxygen is true.