Galvanic Corrosion of Zinc (Sacrificial Anode)
Zn → Zn2+ + 2e−
Overview
Zinc acts as a sacrificial anode when electrically connected to iron or steel, preferentially oxidizing to protect the less reactive metal. Zinc's standard reduction potential (-0.76 V) is more negative than iron's (-0.44 V), so zinc corrodes first. This is the principle of cathodic protection and galvanization.
Participants
| Role | Substance | Coefficient | State |
|---|---|---|---|
| Reactant | Zinc Zn | 1 | (s) |
Everyday Example
Galvanized steel roofing, fencing, and car bodies are coated with zinc that corrodes preferentially, protecting the steel underneath.
Industrial Importance
Zinc galvanizing protects over 100 million tonnes of steel annually. Sacrificial zinc anodes protect ship hulls, pipelines, and offshore structures from corrosion.
Properties
- Type
- Redox
- Reversible
- No
- Energy
- Exothermic
Related Reactions
Aqua Regia Dissolving Gold
Bleaching with Sodium Hypochlorite
Cerium(IV) Reduction by Iron(II)
Chlorine Oxidation of Bromide
Chromate-Dichromate Equilibrium
Contact Process SO₂ Oxidation
Copper Displaced by Iron
Copper Oxidation by Nitric Acid
Copper Patina Formation (Verdigris)
Copper Reduction of Silver Ion
Frequently Asked Questions
What is the equation for Galvanic Corrosion of Zinc (Sacrificial Anode)?
The balanced equation is: Zn → Zn²⁺ + 2e⁻.
What type of reaction is Galvanic Corrosion of Zinc (Sacrificial Anode)?
Galvanic Corrosion of Zinc (Sacrificial Anode) is a redox reaction.
Is Galvanic Corrosion of Zinc (Sacrificial Anode) exothermic or endothermic?
Galvanic Corrosion of Zinc (Sacrificial Anode) is exothermic (releases energy).