Stainless steel does not rust because

Options

A. Chromium and nickel combine with iron
B. Chromium forms an oxide layer and protects iron from rusting
C. Nickel present in it, does not rust
D. Iron forms a hard chemical compound with chromium present in it

Explanation

**Step-by-Step Solution:**

1. **Understanding Stainless Steel Composition:**
- Stainless steel is an alloy primarily composed of iron, with a significant addition of chromium (at least 10.5% by weight). Some stainless steels also contain nickel and other elements.

2. **Role of Chromium:**
- Chromium is the key element that gives stainless steel its corrosion-resistant properties. When stainless steel is exposed to oxygen (from air or water), chromium reacts with oxygen to form a thin, protective oxide layer on the surface of the steel.

3. **Formation of the Oxide Layer:**
- This oxide layer is primarily chromium oxide (Cr2O3). It is very thin, but it is highly adherent and protects the underlying iron from further oxidation (rusting).

4. **Prevention of Rusting:**
- The presence of this oxide layer prevents the iron in the stainless steel from coming into contact with moisture and oxygen, which are necessary for the rusting process (formation of iron oxide).

5. **Conclusion:**
- Therefore, stainless steel does not rust because the chromium in it forms a protective oxide layer that shields the iron from environmental factors that cause rust.

**Final Answer:**
Stainless steel does not rust because chromium forms an oxide layer that protects iron from rusting.

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