Aluminum Hydroxide as Amphoteric Acid with NaOH
Al(OH)3 + NaOH → NaAlO2 + 2H2O
Overview
Aluminum hydroxide dissolves in sodium hydroxide solution, demonstrating its acidic character. The Al(OH)₃ acts as a Lewis acid, accepting OH⁻ to form the aluminate ion [Al(OH)₄]⁻. This amphoteric behavior is characteristic of elements near the metal-nonmetal boundary in the periodic table.
Participants
| Role | Substance | Coefficient | State |
|---|---|---|---|
| Reactant | Aluminum Hydroxide Al(OH)₃ | 1 | (s) |
| Reactant | Sodium Hydroxide NaOH | 1 | (aq) |
| Product | Water H₂O | 2 | (l) |
Everyday Example
The Bayer process for aluminum production exploits this amphoteric behavior, dissolving aluminum oxide in NaOH to separate it from iron oxide impurities.
Industrial Importance
Sodium aluminate is used in water treatment as a coagulant, in paper manufacturing, and in the Bayer process which produces over 130 million tonnes of alumina annually.
Properties
- Type
- Acid-Base
- Reversible
- No
- Energy
- Exothermic
- ΔH
- -20.0 kJ/mol
Related Reactions
Acetic Acid and Sodium Acetate Buffer System
Acetic Acid and Sodium Hydroxide Neutralization
Acetic Acid Dissociation in Water
Aluminum Chloride and Chloride Ion (Lewis Acid-Base)
Aluminum Hydroxide as Amphoteric Base with HCl
Ammonia and Ammonium Chloride Buffer System
Ammonia and Hydrochloric Acid
Ascorbic Acid and Sodium Hydroxide
Barium Hydroxide and Ammonium Thiocyanate (Endothermic)
Benzoic Acid and Sodium Hydroxide
Frequently Asked Questions
What is the equation for Aluminum Hydroxide as Amphoteric Acid with NaOH?
The balanced equation is: Al(OH)₃ + NaOH → NaAlO₂ + 2H₂O.
What type of reaction is Aluminum Hydroxide as Amphoteric Acid with NaOH?
Aluminum Hydroxide as Amphoteric Acid with NaOH is a acid-base reaction.
Is Aluminum Hydroxide as Amphoteric Acid with NaOH exothermic or endothermic?
Aluminum Hydroxide as Amphoteric Acid with NaOH is exothermic (releases energy). The enthalpy change (ΔH) is -20.0 kJ/mol.