Chromium(III) Hydroxide Precipitation

CrCl₃ + 3NaOH → Cr(OH)₃↓ + 3NaCl

Aperçu

Chromium(III) chloride reacts with sodium hydroxide to form a green gelatinous precipitate of chromium(III) hydroxide (Ksp = 6.3 × 10⁻³¹). Cr(OH)₃ is amphoteric, dissolving in both excess acid and excess NaOH. In excess NaOH, it forms the green chromite ion [Cr(OH)₄]⁻.

Participants

Rôle	Substance	Coefficient	État
Réactif	Sodium Hydroxide NaOH	3	(aq)
Produit	Sodium Chloride NaCl	3	(aq)

Exemple du quotidien

The green color of some gemstones like emerald is due to chromium(III) ions, the same oxidation state that produces this green precipitate.

Importance industrielle

Chromium(III) hydroxide precipitation is used in chromium removal from industrial wastewater, particularly from chrome plating and leather tanning effluents.

Propriétés

Type: Precipitation
Réversible: Non
Énergie: Exothermique
ΔH: -90,0 kJ/mol

Réactions associées

Aluminum Hydroxide Precipitation Barium Sulfate Precipitation Cadmium Sulfide Precipitation (Yellow) Calcium Phosphate Precipitation (Bone Mineral) Lead Carbonate Precipitation Magnesium Hydroxide Precipitation Copper Sulfide Precipitation Cobalt(II) Hydroxide Precipitation Mercury(II) Sulfide Precipitation (Vermilion) Iron(III) Hydroxide Precipitation

Frequently Asked Questions

What is the equation for Chromium(III) Hydroxide Precipitation?

The balanced equation is: CrCl₃ + 3NaOH → Cr(OH)₃↓ + 3NaCl.

What type of reaction is Chromium(III) Hydroxide Precipitation?

Chromium(III) Hydroxide Precipitation is a precipitation reaction.

Is Chromium(III) Hydroxide Precipitation exothermic or endothermic?

Chromium(III) Hydroxide Precipitation is exothermic (releases energy). The enthalpy change (ΔH) is -90.0 kJ/mol.