Properties of a substance before and after a change remained same. What might be the nature of the change?

Options

A. Physical change
B. Chemical change
C. Fast change
D. Periodic change

Explanation

To determine the nature of the change when the properties of a substance before and after the change remain the same, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Question**: The question asks about the nature of the change when the properties of a substance do not change before and after the change.

2. **Identify Types of Changes**: There are generally two main types of changes in chemistry: physical changes and chemical changes. We also consider fast changes and periodic changes, but these are less relevant to the properties of substances.

3. **Analyze Physical Change**:
- In a physical change, the substance may change its form or state (like melting, freezing, or dissolving), but its chemical composition remains the same.
- Examples include ice melting into water or sugar dissolving in water. In both cases, the original substance can be recovered, and its properties remain unchanged.

4. **Analyze Chemical Change**:
- In a chemical change, the substance undergoes a transformation that results in the formation of one or more new substances with different properties.
- Examples include rusting of iron or burning wood, where new substances are formed, and the original properties are altered.

5. **Consider Other Types of Changes**:
- Fast changes refer to the speed at which a change occurs but do not inherently indicate whether the properties change.
- Periodic changes are those that occur at regular intervals, but again, they do not directly relate to the properties of the substance.

6. **Conclusion**: Since the properties of the substance remain the same before and after the change, the nature of the change is identified as a **physical change**.

### Final Answer:
The nature of the change is a **physical change**.

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