Micelies are :

Options

A. Ideal solution
B. Associated colloids
C. Adsorbed surfaces
D. Adsorbent solutes

Answer

**Step-by-Step Solution:**

1. **Definition of Micelles:** Micelles are defined as aggregates of surfactant molecules that form in a solution when the concentration of the surfactant exceeds a certain threshold known as the critical micelle concentration (CMC).

2. **Associated Colloids:** Micelles are a type of associated colloid. Associated colloids are substances that behave like normal electrolytes at low concentrations but exhibit colloidal properties at higher concentrations.

3. **Behavior at Different Concentrations:** At low concentrations, associated colloids (like surfactants) dissociate into individual molecules and behave like electrolytes. However, as the concentration increases, these molecules aggregate to form micelles.

4. **Formation of Micelles:** The formation of micelles occurs because the hydrophobic (water-repelling) tails of surfactant molecules cluster together to minimize their exposure to water, while the hydrophilic (water-attracting) heads remain in contact with the surrounding water. This arrangement allows the surfactant to reduce the surface tension of the solution.

5. **Examples of Micelles:** Common examples of micelles include soaps and synthetic detergents. These substances are known to form micelles in aqueous solutions, which help in the emulsification and removal of dirt and grease.

6. **Conclusion:** Therefore, micelles are associated colloids that form when surfactants reach a high concentration in a solution, leading to the aggregation of particles.

**Final Answer:** Micelles are associated colloids that form at high concentrations, with examples including soaps and synthetic detergents.

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