CuS + 2 HNO₃ → H₂ + CuSO₄ + 2 NO

This is an oxidation-reduction (redox) reaction:

CuS is a reducing agent, HNO₃ is an oxidizing agent, HNO₃ is an oxidizing agent.

Reactants:

• CuS – Copper sulfide
  • Other names: Copper monosulfide , Covellite , Copper(II) sulfide , Cupric sulfide
  • Appearance: Black powder or lumps
• HNO₃ – Nitric acid
  • Other names: Aqua fortis , Spirit of niter , Eau forte ... show moreHydrogen nitrate , Acidum nitricum , Nitric acid (> 70% in water) , Fuming nitric acid , Engravers acid , HONO2 , Red fuming nitric acid , RFNA , White fuming nitric acid (WFNA) show less
  • Appearance: Colorless, yellow or red fuming liquid ; Colourless-to-yellow liquid with pungent odour ; Colorless, yellow, or red, fuming liquid with an acrid, suffocating odor. [Note: Often used in an aqueous solution. Fuming nitric acid is concentrated nitric acid that contains dissolved nitrogen dioxide.]

Products:

• H₂
  • Names: Dihydrogen , Hydrogen , H2 ... show moreH₂ , Molecular hydrogen gas , Hydrogen gas , Hydrogen molecule , Molecular hydrogen show less
  • Appearance: Odourless colourless compressed gas
• CuSO₄ – Copper(II) sulfate
  • Other names: Cupric sulphate , Blue vitriol (pentahydrate) , Bluestone (pentahydrate) ... show moreBonattite (trihydrate mineral) , Boothite (heptahydrate mineral) , Chalcanthite (pentahydrate mineral) , Chalcocyanite (mineral) , Cupric sulfate , Copper sulfate (anhydrous) , CuSO4 , Copper sulfate , Cupric sulfate anhydrous , Copper monosulphate , Copper sulfate (1:1) , Cupric sulphate anhydrous , Copper sulphate , Copper(2+) sulfate , Copper(II) sulphate , Copper monosulfate , Cupric sulfate, anhydrous , Cupric sulphate, anhydrous , Sulfuric acid, copper(2+) salt(1:1) show less
  • Appearance: Gray-white (anhydrous) | blue (pentahydrate) ; White hygroscopic crystals
• NO – Nitrogen monoxide , Oxidonitrogen(•) (additive)
  • Other names: Nitric oxide , Nitrogen(II) oxide , Nitric oxide (radical) ... show moreMononitrogen monoxide , (.)NO , EDRF , Nitrogen monooxide , [NO] , Oxido de nitrogeno(ii) , NO(.) , Oxido nitrico , Stickstoff(ii)-oxid , NO , Oxyde azotique , Oxyde nitrique , Stickstoffmonoxid , Nitrosyl , (NO)(.) , Monoxido de nitrogeno , Endothelium-derived relaxing factor , Nitroxide radical , Nitroxyl , Nitrosyl radical , Hydroxyamine , Nitrogen oxide , Nitrogen protoxide , Nitrosyl hydride , Nitric Oxide show less
  • Appearance: Colourless gas ; Colourless compressed gas ; Colorless gas. [Note: Shipped as a nonliquefied compressed gas.]