Zinc Hydroxide as Amphoteric Acid with NaOH
Zn(OH)2 + 2NaOH → Na2[Zn(OH)4]
Overview
Zinc hydroxide dissolves in excess sodium hydroxide to form the soluble tetrahydroxozincate complex. This demonstrates zinc hydroxide's acidic character. The initial white precipitate formed by adding NaOH to Zn²⁺ dissolves upon addition of excess base, a key observation in qualitative analysis.
Participants
| Role | Substance | Coefficient | State |
|---|---|---|---|
| Reactant | Sodium Hydroxide NaOH | 2 | (aq) |
Everyday Example
In qualitative analysis labs, students observe the zinc precipitate dissolving in excess NaOH as proof of zinc's amphoteric nature.
Industrial Importance
The zincate solution is used in alkaline zinc electroplating baths, in galvanizing processes, and in the production of zinc oxide.
Properties
- Type
- Acid-Base
- Reversible
- Yes
- Energy
- Exothermic
- ΔH
- -15.0 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 Acid with NaOH
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)
Frequently Asked Questions
What is the equation for Zinc Hydroxide as Amphoteric Acid with NaOH?
The balanced equation is: Zn(OH)₂ + 2NaOH → Na₂[Zn(OH)₄].
What type of reaction is Zinc Hydroxide as Amphoteric Acid with NaOH?
Zinc Hydroxide as Amphoteric Acid with NaOH is a acid-base reaction. It is reversible under certain conditions.
Is Zinc Hydroxide as Amphoteric Acid with NaOH exothermic or endothermic?
Zinc Hydroxide as Amphoteric Acid with NaOH is exothermic (releases energy). The enthalpy change (ΔH) is -15.0 kJ/mol.