Which metal is used as a coating on steel to prevent corrosion:-

Options

A. Na
B. Ca
C. K
D. Zn

Answer

**Step-by-Step Solution:**

1. **Understanding Corrosion**: Corrosion is the process where metals deteriorate due to chemical reactions, often involving moisture and oxygen. Steel, which is primarily iron, is particularly susceptible to rusting when exposed to these elements.

2. **Preventing Corrosion**: To prevent corrosion, various methods can be employed. One effective method is to coat the metal with another material that can protect it from environmental factors.

3. **Choosing the Coating Metal**: The metal commonly used for coating steel to prevent corrosion is zinc. Zinc is chosen because it is more reactive than iron, which means it will corrode before the iron does, thereby protecting the steel.

4. **Galvanizing Process**: The process of applying a protective zinc coating to steel or iron is known as galvanizing. This involves coating the steel with a thin layer of zinc.

5. **Mechanism of Protection**: The zinc coating acts as a barrier that prevents oxygen and moisture from reaching the underlying steel. As a result, the steel does not rust or corrode, as the zinc sacrifices itself to protect the steel.

6. **Conclusion**: Therefore, the metal used as a coating on steel to prevent corrosion is zinc.

**Final Answer**: Zinc is used as a coating on steel to prevent corrosion.

---