H₂SO₄ + 8 HY → 4 H₂O + H₂S + 4 Y₂

This is an oxidation-reduction (redox) reaction:

H₂SO₄ is an oxidizing agent, HY is a reducing agent, HY is an oxidizing agent.

Reactants:

• H₂SO₄ – Sulfuric acid
  • Other names: Oil of vitriol , Sulfuric acid, concentrated (> 51% and < 100%) , H2SO4 ... show moreSulphuric acid , Battery acid , Hydrogen sulfate , [SO2(OH)2] , [S(OH)2O2] , Sulfuric acid (aqueous) show less
  • Appearance: Clear, colorless liquid ; Odourless colourless oily hygroscopic liquid ; Colorless to dark-brown, oily, odorless liquid. [Note: Pure compound is a solid below 51°F. Often used in an aqueous solution.]
• HY

Products:

• 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
• H₂S – Hydrogen sulfide
  • Other names: Dihydrogen monosulfide , Dihydrogen sulfide , Sewer gas ... show moreSulfane , Sulfurated hydrogen , Sulfureted hydrogen , Sulfuretted hydrogen , Sulfur hydride , Hydrosulfuric acid , Hydrothionic acid , Thiohydroxic acid , Sulfhydric acid , H2S , Hydrogen sulphide , [SH2] , Hydrogen monosulfide , Sulfide , Zwavelwaterstof , Sulfur hydroxide , Siarkowodor , Idrogeno solforato , Dihydrogen disulfide , Hydrosulfurate , Hepatate , Sour gas , Hepatic gas , Stink dAMP , Hepatic acid , Dihydrogen sulphide show less
  • Appearance: Colorless gas ; Colourless compressed liquefied gas with characteristic odour of rotten eggs ; Colorless gas with a strong odor of rotten eggs. [Note: Sense of smell becomes rapidly fatigued & can NOT be relied upon to warn of the continuous presence of H2S. Shipped as a liquefied compressed gas.]
• Y₂