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.