Chromate-Dichromate Equilibrium

2CrO42− + 2H+ ⇌ Cr2O72− + H2O

Übersicht

Chromate (yellow, CrO₄²⁻) converts to dichromate (orange, Cr₂O₇²⁻) in acidic solution and vice versa in basic solution. This pH-dependent equilibrium involves condensation of two tetrahedral chromate units. While chromium remains at +6 throughout, this equilibrium is fundamental to Cr(VI) redox chemistry.

Teilnehmer

Rolle Substanz Koeffizient Zustand
Produkt Water H₂O 1 (l)

Alltägliches Beispiel

Adding acid to yellow potassium chromate solution turns it orange, and adding base reverses it, demonstrating Le Chatelier's principle.

Industrielle Bedeutung

Chromate/dichromate equilibrium is important in chrome plating, leather tanning, and in understanding Cr(VI) environmental contamination.

Eigenschaften

Typ
Redox
Reversibel
Ja
Energie
Exotherm
ΔH
-14,0 kJ/mol

Verwandte Reaktionen

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 Chromate-Dichromate Equilibrium?
The balanced equation is: 2CrO₄²⁻ + 2H⁺ ⇌ Cr₂O₇²⁻ + H₂O.
What type of reaction is Chromate-Dichromate Equilibrium?
Chromate-Dichromate Equilibrium is a redox reaction. It is reversible under certain conditions.
Is Chromate-Dichromate Equilibrium exothermic or endothermic?
Chromate-Dichromate Equilibrium is exothermic (releases energy). The enthalpy change (ΔH) is -14.0 kJ/mol.