When a substance comes in colloidal state the surface area of the particles

Options

A. Increases
B. Decreases
C. Remains unchanged
D. First increases then decreases

Explanation

To solve the question regarding the change in surface area of particles when a substance transitions to a colloidal state, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Colloidal State**:
- A colloidal state refers to a mixture where one substance is dispersed evenly throughout another. The particles in a colloid are typically larger than molecules but smaller than those in a suspension.

2. **Particle Size in Colloids**:
- In a colloidal state, the particles are usually in the range of 1 nanometer to 1 micrometer in size. This small size is crucial because it affects the surface area of the particles.

3. **Surface Area Calculation**:
- Surface area is inversely related to particle size. As the size of the particles decreases, the total surface area increases. This is because smaller particles have a greater total surface area compared to larger particles of the same mass.

4. **Conclusion**:
- Therefore, when a substance comes into a colloidal state, the surface area of the particles increases due to their smaller size compared to the original substance.

5. **Final Answer**:
- The correct answer to the question is that the surface area of the particles **increases** when a substance comes into a colloidal state.