Which is not a colloidal solution ?

Options

A. Smoke
B. Ink
C. Air
D. Blood

Answer

To determine which option is not a colloidal solution, we need to understand the characteristics of colloidal solutions and differentiate them from other types of mixtures.

### Step-by-Step Solution:

1. **Definition of Colloidal Solutions**:
- Colloidal solutions are heterogeneous mixtures consisting of a dispersed phase (solutes) and a dispersion medium (solvent). The particle size in colloidal solutions typically ranges from \(10^{-9}\) meters to \(10^{-6}\) meters.

2. **Identifying the Options**:
- We need to analyze the given options to identify which one does not fit the criteria of a colloidal solution.

3. **Examine Each Option**:
- **Option A**: Smoke
- Smoke is a colloidal solution where solid particles (dispersed phase) are mixed in a gas (dispersion medium). This is classified as an aerosol.
- **Option B**: Ink
- Ink is a colloidal solution where solid particles (dispersed phase) are mixed in a liquid (dispersion medium). This is classified as a sol.
- **Option C**: Air
- Air is a homogeneous mixture of various gases and does not contain dispersed particles in the colloidal size range. Therefore, it is not a colloidal solution.
- **Option D**: Blood
- Blood is a colloidal solution where cells (dispersed phase) are suspended in plasma (dispersion medium). This is also classified as a sol.

4. **Conclusion**:
- Based on the analysis, **Option C (Air)** is not a colloidal solution as it is a homogeneous mixture of gases.

### Final Answer:
**Option C: Air is not a colloidal solution.**

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