Step 1: Understanding the Concept:
Coagulation is the process of settling or precipitation of colloidal particles by neutralising their charge.
Step 2: Key Formula or Approach:
Identify methods that destabilize a sol versus those that dilute or stabilize it.
Step 3: Detailed Explanation:
- Electrophoresis: Colloidal particles move toward oppositely charged electrodes, discharge, and coagulate.
- Mixing two oppositely charged sols: Mutual neutralization occurs, leading to coagulation (mutual coagulation).
- Boiling: Increases collisions and reduces the adsorbed layer of electrolyte, causing particles to come closer and coagulate.
- Adding excess solvent: This is a process of dilution. Diluting a sol generally increases its stability rather than causing the particles to clump together. Thus, it does not result in coagulation.
Step 4: Final Answer:
Adding excess solvent does not result in coagulation.