8 P (s) + 3 KOH (aq) + 9 H₂O (l) → 5 PH₃ (g) + 3 KH₂PO₄ (aq)

This is an oxidation-reduction (redox) reaction:

P is both an oxidizing and a reducing agent (disproportionation (dismutation)).

Reactants:

• P
• KOH – Potassium hydroxide
  • Other names: Caustic potash , Lye , Potash lye ... show morePotassia , Potassium hydrate , KOH , E525 , Potassium lye , Lye [Potassium hydroxide] show less
  • Appearance: White solid, deliquescent ; White hygroscopic solid in various forms ; Odorless, white or slightly yellow lumps, rods, flakes, sticks, or pellets. [Note: May be used as an aqueous solution.]
• H₂O – Water, oxidane
  • Other names: Water (H2O) , Hydrogen hydroxide (HH or HOH) , Hydrogen oxide ... show moreDihydrogen monoxide (DHMO) (systematic name) , Hydrogen monoxide , Dihydrogen oxide , Hydric acid , Hydrohydroxic acid , Hydroxic acid , Hydrol , Μ-oxido dihydrogen , Κ1-hydroxyl hydrogen(0) show less
  • Appearance: White crystalline solid, almost colorless liquid with a hint of blue, colorless gas

Products:

• PH₃ – Phosphane
  • Other names: Phosphine , Phosphamine , Phosphorus trihydride ... show morePhosphorated hydrogen , Hydrogen phosphide , Phosphorus hydride , [PH3] , PH3 show less
  • Appearance: Colorless gas ; Colourless compressed liquefied gas ; Colorless gas with a fish- or garlic-like odor. [pesticide] [Note: Shipped as a liquefied compressed gas. Pure compound is odorless.]
• KH₂PO₄ – Potassium dihydroxidodioxidophosphate(1−)
  • Other names: Monopotassium phosphate , Potassium phosphate monobasic; , Phosphoric acid ... show moreMonopotassium salt; , Potassium biphosphate , Monobasic potassium phosphate , Potassium dihydrogen phosphate , KDP , MKP , Potassium phosphate, monobasic , Phosphoric acid, potassium salt (1:1) , Orthophosphoric acid, monopotassium salt , Sorensen's potassium phosphate , Potassium dihydrogen orthophosphate , Potassium acid phosphate , Monopotassium orthophosphate , Monopotassium monophosphate , Phosphoric acid, monopotassium salt , Monopotassium dihydrogen phosphate , Potassium phosphate , Potassium phosphate monobasic , Potassium phosphate,monobasic , Potassium phosphate monobasic (anhydrous) , Monopotassium dihydrogen monophosphate , Monopotassium dihydrogen orthophosphate , E340i show less
  • Appearance: White powder | deliquescent ; Colourless crystals or white crystalline powder