Which one of the following is a chemical change?

Options

A. Melting of ice
B. Burning of coal
C. Magnetizing of iron
D. Reducing a solid stone to a fine powder

Answer

To determine which of the following is a chemical change, we need to understand the characteristics of chemical changes compared to physical changes.

### Step-by-Step Solution:

1. **Understanding Chemical Change**: A chemical change occurs when a new substance is formed. This is the key characteristic that differentiates it from a physical change, where no new substances are created.

2. **Analyzing the Options**:
- **Option 1: Melting of Ice**:
- When ice melts, it changes from a solid to a liquid (water).
- No new substance is formed; it is still H2O in a different state.
- **Conclusion**: This is a physical change.

- **Option 2: Burning of Coal**:
- When coal burns, it reacts with oxygen and produces carbon dioxide and other substances.
- New substances are formed in this process.
- **Conclusion**: This is a chemical change.

- **Option 3: Magnetization of Iron**:
- Magnetizing iron involves inducing magnetic properties but does not create a new substance.
- The iron remains iron, just with a different property.
- **Conclusion**: This is a physical change.

- **Option 4: Reducing a Solid Stone to a Fine Powder**:
- Grinding a stone into powder changes its physical form but does not change its chemical composition.
- No new substance is formed.
- **Conclusion**: This is a physical change.

3. **Final Conclusion**:
- After analyzing all the options, the only process that results in the formation of new substances is the burning of coal.
- Therefore, **the correct answer is Option 2: Burning of Coal**.