Sulfur Dioxide Reduction of Dichromate

Cr₂O₇²⁻ + 3SO₂ + 2H⁺ → 2Cr³⁺ + 3SO₄²⁻ + H₂O

Aperçu

Sulfur dioxide reduces orange dichromate to green chromium(III) while being oxidized to sulfate. This reaction changes the solution color from orange to green and is used as a test for SO₂ gas. Cr(VI) gains 3 electrons per atom while S(IV) loses 2 electrons per atom.

Participants

Rôle	Substance	Coefficient	État
Réactif	Sulfur Dioxide SO₂	3	(g)
Produit	Water H₂O	1	(l)

Exemple du quotidien

Dichromate-impregnated paper is used as a sensitive test for sulfur dioxide gas, turning from orange to green in its presence.

Importance industrielle

This reaction is relevant to flue gas monitoring, environmental SO₂ detection, and understanding chromium redox chemistry in industrial processes.

Propriétés

Type: Redox
Réversible: Non
Énergie: Exothermique
ΔH: -850,0 kJ/mol

Réactions associées

Iron(II) to Iron(III) Oxidation by Oxygen Bleaching with Sodium Hypochlorite Copper Reduction of Silver Ion Aqua Regia Dissolving Gold Cerium(IV) Reduction by Iron(II) Chlorine Oxidation of Bromide Copper Oxidation by Nitric Acid Hypochlorite Oxidation of Hydrogen Peroxide Hydrogen Peroxide as Oxidizing Agent (Acidic) Displacement of Hydrogen from Acid by Magnesium

Frequently Asked Questions

What is the equation for Sulfur Dioxide Reduction of Dichromate?

The balanced equation is: Cr₂O₇²⁻ + 3SO₂ + 2H⁺ → 2Cr³⁺ + 3SO₄²⁻ + H₂O.

What type of reaction is Sulfur Dioxide Reduction of Dichromate?

Sulfur Dioxide Reduction of Dichromate is a redox reaction.

Is Sulfur Dioxide Reduction of Dichromate exothermic or endothermic?

Sulfur Dioxide Reduction of Dichromate is exothermic (releases energy). The enthalpy change (ΔH) is -850.0 kJ/mol.