The Zn acts as sacrificial of cathodic protection to prevent rusting of iron because:

Options

A. `E_(OP)^(@)` of `ZnltE_(OP)^(@)` of Fe
B. `E_(OP)^(@)` of `ZngtE_(OP)^(@)` of Fe
C. `E_(OP)^(@)` of `Zn=E_(OP)^(@)` of Fe
D. Zn is cheaper than iron

Answer

### Step-by-Step Solution:

1. **Understanding Rusting of Iron**:
- Rusting is the process where iron reacts with oxygen and moisture to form rust, which is primarily hydrated ferric oxide (Fe2O3·xH2O).
- In this process, iron (Fe) is oxidized, meaning it loses electrons and typically goes from a zero oxidation state to a +2 or +3 oxidation state.

2. **Role of Zinc in Cathodic Protection**:
- Zinc is used as a sacrificial anode in cathodic protection systems to prevent rusting of iron.
- When zinc is applied to iron, it serves as a protective layer.

3. **Oxidation Potentials**:
- The oxidation potential of a metal is a measure of its tendency to lose electrons and be oxidized.
- Zinc has a higher oxidation potential compared to iron. This means that zinc is more likely to oxidize than iron.

4. **Mechanism of Protection**:
- When zinc is in contact with iron, it will preferentially oxidize (lose electrons) instead of iron.
- The reaction can be represented as:
\[ \text{Zn} \rightarrow \text{Zn}^{2+} + 2e^- \]
- As zinc oxidizes, it protects the iron from losing electrons and thus prevents rust formation.

5. **Conclusion**:
- Since zinc oxidizes before iron, it effectively protects the iron from rusting. Therefore, the statement that "the oxidation potential of zinc is greater than the oxidation potential of iron" is true, making zinc an effective sacrificial anode.

### Final Answer:
Zinc acts as a sacrificial anode for cathodic protection to prevent rusting of iron because the oxidation potential of zinc is greater than that of iron, leading to zinc oxidizing preferentially and protecting the iron from rusting.

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