Question

What is the chemical equation of exposing phosphorus in air

Answer 1

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Reaction of phosphorus with air

It spontanteously ignites in air at about room temperature to form "phosphorus pentoxide" - actually tetraphosphorus decaoxide, P4O10.

Answer 2

P + O2 = P2O5

Balanced equation will be ~

2P + 5O2 = 2P2O5

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