As₄O₆ + 12 Cu + 12 HCl → 12 CuCl + 4 As + 6 H₂O

This is an oxidation-reduction (redox) reaction:

As₄O₆ is an oxidizing agent, Cu is a reducing agent.

Reactants:

• As₄O₆
• Cu
  • Names: Copper , Copper (dusts and mists, as Cu) , Cu ... show moreCU-7 , Tatum-T , Paragard T 380A , Element 29 , Cuprum , Copper metal dusts , Copper metal fumes show less
  • Appearance: Solid in various forms. turns green on exposure to moist air ; Reddish, lustrous, malleable, odorless solid.
• 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:

• CuCl – Copper(I) chloride
  • Other names: Cuprous chloride , Cuproid , Cu-lyt ... show moreCuCl , Copper chloride (CuCl) , Copper chloride , Dicopper dichloride , Copper(1+) chloride , Copper monochloride show less
  • Appearance: White powder, slightly green from oxidized impurities
• As
  • Names: Arsenic , Grey arsenic
  • Appearance: Brittle grey metallic-looking 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