Aluminum Hydroxide Precipitation

AlCl₃ + 3NaOH → Al(OH)₃↓ + 3NaCl

Aperçu

Aluminum chloride reacts with sodium hydroxide to form a white gelatinous precipitate of aluminum hydroxide (Ksp = 3 × 10⁻³⁴). Al(OH)₃ is amphoteric: it dissolves in excess NaOH to form aluminate [Al(OH)₄]⁻. The gelatinous precipitate is an excellent flocculating agent.

Participants

Rôle	Substance	Coefficient	État
Produit	Aluminum Hydroxide Al(OH)₃	1	(s)
Produit	Sodium Chloride NaCl	3	(aq)

Exemple du quotidien

Water treatment plants use aluminum salts to form Al(OH)₃ flocs that trap suspended particles, clarifying drinking water.

Importance industrielle

Al(OH)₃ coagulation is the most widely used water purification method globally. Aluminum hydroxide is also used as a fire retardant and antacid.

Propriétés

Type: Precipitation
Réversible: Non
Énergie: Exothermique
ΔH: -115,0 kJ/mol

Réactions associées

Barium Carbonate Precipitation Barium Sulfate Precipitation Cadmium Sulfide Precipitation (Yellow) Calcium Fluoride Precipitation (Fluorite) Calcium Phosphate Precipitation (Bone Mineral) Chromium(III) Hydroxide Precipitation Lead Carbonate Precipitation Lead Chloride Precipitation Calcium Carbonate Precipitation Iron(III) Hydroxide Precipitation

Frequently Asked Questions

What is the equation for Aluminum Hydroxide Precipitation?

The balanced equation is: AlCl₃ + 3NaOH → Al(OH)₃↓ + 3NaCl.

What type of reaction is Aluminum Hydroxide Precipitation?

Aluminum Hydroxide Precipitation is a precipitation reaction.

Is Aluminum Hydroxide Precipitation exothermic or endothermic?

Aluminum Hydroxide Precipitation is exothermic (releases energy). The enthalpy change (ΔH) is -115.0 kJ/mol.