Collidal solution is a heterogeneous solution which contains particle of intermediate size, i.e., (diameter between 1 and 1000 nm) colloidal is not a substance but it is a state of a substance which depends upon the molecular size. Colloidal solutions are intermediate between ture solution and suspensions.
The colloidal solution of a solid as the disperesed phase and a gas as the dispersed medium is called

Options

A. Sol
B. Sloid foam
C. Aerosol
D. Gel

Answer

To solve the question regarding the colloidal solution of a solid as the dispersed phase and a gas as the dispersed medium, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Colloidal Solutions**:
- A colloidal solution is a heterogeneous mixture where the particle size is between 1 nm and 1000 nm. It is important to recognize that colloids are not a specific substance but rather a state of matter that depends on the size of the particles.

**Hint**: Recall the definition of colloidal solutions and their characteristics, including particle size.

2. **Identifying the Phases**:
- In the given question, we have a solid as the dispersed phase and a gas as the dispersed medium. This means we need to identify what type of colloidal system this represents.

**Hint**: Think about the classification of colloids based on the states of the dispersed phase and the dispersion medium.

3. **Classifying the Colloid**:
- Colloids can be classified based on the states of the dispersed phase and the dispersion medium. The combinations include:
- Solid in liquid (sol)
- Liquid in liquid (emulsion)
- Gas in liquid (aerosol)
- Solid in gas (aerosol)
- Gas in solid (solid foam)
- Here, since we have a solid dispersed in a gas, we are looking for the term that describes this type of colloid.

**Hint**: Recall the terms used for different types of colloids. Focus on the combination of solid and gas.

4. **Identifying the Correct Term**:
- The colloidal solution of a solid dispersed in a gas is specifically known as an **aerosol**. Common examples of aerosols include dust particles in the air and smoke.

**Hint**: Remember that aerosols are commonly found in everyday life, such as in the atmosphere.

5. **Conclusion**:
- Therefore, the colloidal solution of a solid as the dispersed phase and a gas as the dispersed medium is called an **aerosol**.

**Final Answer**: The answer is **aerosol**.

### Summary of the Steps:
- Understand colloidal solutions.
- Identify the phases involved.
- Classify the colloidal system.
- Identify the correct term for the combination of solid and gas.
- Conclude with the answer.