Bredigs arc method involves :

Options

A. dispersion of metal
B. condenstion of metal
C. dispersion as well as condenstion
D. neither dispersion nor condensation

Answer

**Step-by-Step Solution:**

1. **Understanding Bredig's Arc Method**:
- Bredig's arc method is a technique used for the preparation of colloidal solutions of metals, particularly gold and silver. It is also referred to as the electrical disintegration method.

2. **Process Description**:
- In this method, two metal rods (typically made of gold or silver) are placed in a dispersion medium, which is usually a solution of potassium hydroxide (KOH).
- An electric arc is created between the two rods. The intense heat generated by the arc causes the metal rods to vaporize.

3. **Dispersion of Metal**:
- The vaporized metal particles are dispersed in the surrounding medium. This process is known as dispersion, where the metal is broken down into smaller particles.

4. **Condensation of Metal**:
- As the vaporized metal comes into contact with the cooler regions of the dispersion medium (cold water), it condenses back into small colloidal particles. This process is known as condensation.

5. **Conclusion**:
- Therefore, Bredig's arc method involves both the dispersion of metal (when the metal vaporizes) and the condensation of metal (when the vapor aggregates to form colloidal particles).
- Hence, the correct answer is option 3: dispersion as well as condensation of metal.

**Final Answer**: Option 3 - Dispersion as well as condensation of metal.

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