5 As₂O₃ (s) + 4 KMnO₄ (aq) + 12 HCl (aq) → 5 As₂O₅ (aq) + 4 MnCl₂ (aq) + 4 KCl (aq) + 6 H₂O (l)

This is an oxidation-reduction (redox) reaction:

KMnO₄ is an oxidizing agent, As₂O₃ is a reducing agent.

Reactants:

• As₂O₃ – Diarsenic trioxide
  • Other names: Arsenic trioxide , Arsenic(III) oxide , Arsenic sesquioxide ... show moreArseneous oxide , Ratsbane , Arseneous anhydride , White arsenic , Aqua Tofani , Arsenious Trioxide , Arsentrioxide , Arseni Trioxydum , Arsenious Acid Anhydride , Arsenic Oxidearsenous Trioxide , Arsenious Acid , Anhydride Arsenieux , Arsenolite , Arsenous oxide , Diarsenic oxide , Arsenic oxide , Arsenous oxide anhydride , Acide Arsenieux , Arsenigen Saure , Arsenic Blanc , As₂O₃ , Arsenic(III)oxide , Arsenous acid anhydride show less
  • Appearance: White solid ; White lumps or crystalline powder
• KMnO₄ – Potassium manganate(VII)
  • Other names: Potassium permanganate , Chameleon mineral , Condy's crystals ... show morePermanganate of potash Hypermangan , Permanganic acid potassium salt show less
  • Appearance: Purplish-bronze-gray needles | magenta–rose in solution ; Dark purple crystals
• HCl – Chlorane , Hydrogen chloride
  • Other names: Hydrochloric acid , M , Uriatic acid ... show moreHydronium chloride , Chlorhydric Acid , Hydrochloric acid gas , HCl , Anhydrous hydrogen chloride , Hydrochloric acid, anhydrous , Aqueous hydrogen chloride , [Note: Often used in an aqueous solution.] show less
  • Appearance: Colorless, transparent liquid, fumes in air if concentrated ; Colorless gas ; Colourless compressed liquefied gas with pungent odour ; Colorless to slightly yellow gas with a pungent, irritating odor. [Note: Shipped as a liquefied compressed gas.]

Products:

• As₂O₅
  • Names: Diarsenic pentoxide , Arsenic(V) oxide , Arsenic oxide ... show moreArsenic anhydride , Arsenic pentoxide , Arsenic (V) oxide , Arsenic acid anhydride show less
  • Appearance: White hygroscopic powder ; White hygroscopic powder
• MnCl₂ – Manganese(II) chloride , Manganese dichloride
  • Other names: Manganous chloride , Manganous dichloride , Manganese(II) chloride (1:2) ... show moreManganese bichloride , Manganese chloride anhydrous , Manganese chloride , Manganese(II) dichloride show less
  • Appearance: Pink solid (tetrahydrate)
• KCl
  • Names: Potassium chloride , Sylvite , Muriate of potash ... show moreKlor-Con M15 , K-Lease , Klor-Con 8 , K+10 , K+8 , Klor-Con M10 , Micro-K 10 , Kato , Kaon Cl-10 , Kaon-Cl , Kaon Cl , Micro-K , Klor-Con 10Meq , Klor-Con 10 , Micro-K Ls , K-dur , Klor-Con , Klor-Con M20 , Slow-K , Ten-K , Klotrix , [KCl] , Kaliumchlorid , Chloride of potash , Kaon-CL 10 , Klor-CON , KCl , Monopotassium chloride , K-Tab , Chlorid draselny , Potassium Chloride show less
  • Appearance: White crystalline solid ; Colourless hygroscopic crystals
• 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