3 H₂O + P₂O₃ → 2 H₃PO₃

Reactants:

• 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
• P₂O₃
  • Names: Phosphorus trioxide , Phosphorus(III) oxide , Phosphorus sesquioxide ... show morePhosphorous oxide , Phosphorous anhydride , Tetraphosphorous hexoxide show less
  • Appearance: Colourless monoclinic crystals or liquid

Products:

• H₃PO₃ – Phosphonic acid
  • Other names: Phosphorous acid , Dihydroxyphosphine oxide
  • Appearance: White solid | deliquescent