In which of the following . Tyndall effect is not observed ?

Options

A. Smoke
B. Emulsion
C. Sugar solution
D. Gold sol

Answer

To determine in which of the following the Tyndall effect is not observed, we need to understand the Tyndall effect and the types of mixtures involved:

### Step-by-Step Solution:

1. **Understanding the Tyndall Effect**:
- The Tyndall effect is the scattering of light by particles in a colloid or in very fine suspensions. It is observed when light passes through a colloidal solution, making the path of the light beam visible.

2. **Identifying Particle Sizes**:
- **True Solutions**: In true solutions, the particle size is less than 1 nanometer. These particles are too small to scatter light, hence the Tyndall effect is not observed.
- **Colloidal Solutions**: In colloidal solutions, the particle size ranges from 1 nanometer to 1000 nanometers. These particles are large enough to scatter light, thus the Tyndall effect is observed.
- **Suspensions**: In suspensions, the particle size is greater than 1000 nanometers. These larger particles also scatter light, so the Tyndall effect is observed.
- **Emulsions**: Emulsions are mixtures of two liquids where one is dispersed in the other, and they can also show the Tyndall effect due to the presence of colloidal particles.

3. **Analyzing the Options**:
- If the options include a true solution (e.g., sugar solution), colloidal solution (e.g., gold sol), and a suspension (e.g., smoke), we can conclude:
- True Solution: No Tyndall effect (particle size < 1 nm)
- Colloidal Solution: Tyndall effect observed (particle size between 1 nm and 1000 nm)
- Suspension: Tyndall effect observed (particle size > 1000 nm)

4. **Conclusion**:
- The option that represents a true solution will be the one where the Tyndall effect is not observed.

### Final Answer:
The Tyndall effect is not observed in a true solution (e.g., sugar solution).

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