Chromate-Dichromate Equilibrium

2CrO₄²⁻ + 2H⁺ ⇌ Cr₂O₇²⁻ + H₂O

Tổng quan

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.

Người tham gia

Vai trò	Chất	Hệ số	Trạng thái
Sản phẩm	Water H₂O	1	(l)

Ví dụ thực tế

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

Tầm quan trọng công nghiệp

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

Tính chất

Loại: Redox
Thuận nghịch: Có
Năng lượng: Tỏa nhiệt
ΔH: -14,0 kJ/mol

Phản ứng liên quan

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.