P₂O₅ + 6 KOH → 2 K₃PO₄ + 3 H₂O

This is an acid-base reaction (neutralization): P₂O₅ is an acid, KOH is a base.

Reactants:

• P₂O₅
  • Names: Phosphorus pentoxide , Diphosphorus pentoxide , Phosphorus(V) oxide ... show morePhosphoric anhydride , Tetraphosphorus decaoxide , Tetraphosphorus decoxide , Phosphorus pentaoxide show less
  • Appearance: White powder | very deliquescent | odorless ; Hygroscopic white crystals or powder
• 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.]

Products:

• K₃PO₄ – Potassium phosphate , Potassium tetraoxidophosphate(3−)
  • Other names: Tripotassium phosphate , Tribasic , Tribasic potassium phosphate ... show moreE340iii , E340(iii) show less
  • Appearance: White deliquescent powder
• 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