Which of the following statements is correct?a)Iron and rust are same ...
**Explanation:**
Rusting of iron is a chemical change. Let's understand why this statement is correct.
**Chemical Change:**
A chemical change is a process that leads to the formation of a new substance with different properties from the original substance. In a chemical change, the atoms rearrange themselves, forming new bonds and breaking old bonds.
**Rusting of Iron:**
When iron comes in contact with oxygen and moisture, it undergoes a chemical reaction called rusting. Rust is the product of this reaction, and it is formed by the combination of iron, oxygen, and water molecules.
**Evidence of Rusting as a Chemical Change:**
1. **Formation of New Substance:** When iron rusts, a new compound called iron(III) oxide is formed. This compound has different properties than iron.
2. **Color Change:** Iron is silver-gray in color, while rust is reddish-brown. This color change indicates the formation of a new substance.
3. **Irreversibility:** Rusting is an irreversible process. Once iron starts rusting, it cannot be easily reversed or converted back to pure iron.
**Comparison with Other Statements:**
a) Iron and rust are not the same substance. Iron is a pure element, while rust is a compound formed by the reaction of iron with oxygen and water. They have different chemical compositions and properties.
c) The removal of rust from the surface of iron is a physical change. It involves the scraping or cleaning off of the rust, but the chemical composition of the iron remains the same.
**Conclusion:**
Based on the evidence provided, the statement that "Rusting of iron is a chemical change" is correct. It involves the formation of a new substance (rust) with different properties from the original substance (iron).
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