Which of the following is a chemical change?

Options

A. Melting of ice
B. Dissolving salt in water
C. Rusting of iron
D. Boiling of water into steam

Explanation

To determine which of the following options represents a chemical change, we need to analyze each option based on the definition of a chemical change. A chemical change occurs when a substance transforms into a different substance with new properties, while a physical change involves a change in the state or appearance of a substance without altering its chemical composition.

### Step-by-Step Solution:

1. **Analyze Option A: Melting of Ice**
- When ice (solid H2O) melts, it changes from a solid to a liquid state (H2O).
- The chemical composition remains the same (H2O), and only the physical state changes.
- **Conclusion**: This is a physical change.

2. **Analyze Option B: Dissolving Salt in Water**
- When salt (NaCl) is dissolved in water, it separates into its ions (Na⁺ and Cl⁻) but does not form a new compound.
- The chemical composition of the salt remains unchanged.
- **Conclusion**: This is also a physical change.

3. **Analyze Option C: Rusting of Iron**
- Rusting involves iron (Fe) reacting with oxygen (O2) and water (H2O) to form rust (Fe2O3·xH2O).
- This process results in the formation of a new compound (rust) with different properties than the original iron.
- **Conclusion**: This is a chemical change.

4. **Analyze Option D: Boiling of Water into Steam**
- Boiling water changes it from liquid (H2O) to vapor (steam).
- The chemical composition remains the same (H2O), and only the physical state changes.
- **Conclusion**: This is a physical change.

### Final Conclusion:
- Among the options provided, **Option C: Rusting of Iron** is the only chemical change.