In a colloidal state the particle size of the dispersed phase range between \(10^3\) to \(10^6\) pm and colloidal sol is heterogenous in nature. Based on the nature of interaction between the dispersed phase and dispersion medium colloidal sol are classified as lyophilic and lyophobic. Stability of sol is due to presence of charge on the sol particles and the neutralization of the same is known as coagulation or precipitation.

Based on this answer the following:

Bredig's arc method is:

To prepare colloidal solution

The correct answer is option 2. To prepare colloidal solution.

Bredig's arc method is a technique used to prepare colloidal solutions, particularly colloidal suspensions of metals. Here's a more detailed explanation of how the method works:

1. Setup: The setup involves two metal electrodes (often made of the metal to be dispersed) placed in a suitable dispersion medium, which is typically a liquid such as water. The electrodes are positioned close to each other but not touching, and they are connected to a high-voltage power source.

2. Passage of Electric Arc: When the high voltage is applied across the electrodes, an electric arc is formed between them. This arc generates intense heat due to the resistance of the air between the electrodes.

3. Vaporization of Metal: The high temperature produced by the electric arc causes the metal electrodes to vaporize. The metal atoms or molecules in the vapor state are highly energetic.

4. Condensation and Formation of Colloidal Particles: As the vaporized metal atoms or molecules move away from the high temperature region near the electrodes, they encounter the cooler dispersion medium. Here, they lose thermal energy and undergo condensation, forming small particles of the metal.

5. Dispersal in Dispersion Medium: These newly formed metal particles are then dispersed throughout the dispersion medium (solvent) to create a colloidal suspension or solution. The particles are typically very fine, ranging in size from a few nanometers to a few micrometers.

6. Stabilization: To prevent the colloidal particles from aggregating and settling out of the solution, stabilizing agents may be added. These agents help to maintain the dispersion of the particles by providing electrostatic or steric stabilization.

Overall, Bredig's arc method allows for the production of colloidal solutions containing fine metal particles dispersed in a liquid medium. This method is commonly used in various fields, including materials science, nanotechnology, and catalysis, where finely divided metals are required for specific applications.