CuS + I₂ + 2 HCl → CuCl₂ + S + 2 HI

This is an oxidation-reduction (redox) reaction:

CuS is a reducing agent, I₂ is an oxidizing agent.

Reactants:

• CuS – Copper sulfide
  • Other names: Copper monosulfide , Covellite , Copper(II) sulfide , Cupric sulfide
  • Appearance: Black powder or lumps
• I₂
  • Names: Iodine , Jod , Iode ... show moreIodio , Yodo , Iodine crystals , Molecular iodine show less
  • Appearance: Bluish black or dark purple crystals with pungent odour ; Violet solid with a sharp, characteristic odor.
• 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:

• CuCl₂
  • Names: Copper(II) chloride , Cupric chloride , Copper chloride ... show moreCopper(2+) chloride , Cupric chloride anhydrous , Coclor , Copper(II) chloride (1:2) , Copper chloride (CuCl2) , Cupric dichloride , Copper(2+)chloride , Copper dichloride , Copper bichloride , CuCl2 , Cupric Chloride show less
  • Appearance: Yellow-brown solid (anhydrous) | blue-green solid (dihydrate)
• S
  • Names: Sulfur , S , Sulphur ... show moreElement 16 , Flowers of sulfur , Flour sulfur , Brimstone show less
  • Appearance: Yellow solid in various forms
• HI – Iodane
  • Other names: Hydroiodic acid , Hydrogen iodide , Hydronium iodide ... show moreHI , Anhydrous hydriodic acid show less
  • Appearance: Colorless liquid ; Colorless gas ; Colourless compressed liquefied gas with pungent odour