H₃PO₄ (aq) + 3 KOH (aq) → K₃PO₄ (aq) + 3 H₂O (l)

This is an acid-base reaction (neutralization): H₃PO₄ is an acid, KOH is a base.

Reactants:

• H₃PO₄
  • Names: Phosphoric acid , Orthophosphoric acid , Phosphoric(V) acid ... show moreWhite phosphoric acid , [PO(OH)3] , H3PO4 , E338 , Phosphoric acid (aqueous) show less
  • Appearance: Hygroscopic colourless crystals ; Thick, colorless, odorless, crystalline solid. [Note: Often used in an aqueous solution.]
• 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