The substances which behave as colloidal solutions at higher concentration are called

Options

A. associated colloids
B. multimolecular colloids
C. macromolecular colloids
D. protective colloids.

Explanation

To solve the question, "The substances which behave as colloidal solutions at higher concentration are called," we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Colloidal Solutions**:
- Colloidal solutions are mixtures where one substance (the dispersed phase) is distributed evenly throughout another substance (the continuous phase).

2. **Concentration Effects**:
- At low concentrations, certain substances behave like normal electrolytes, meaning they dissolve and dissociate into ions without forming colloidal structures.

3. **Behavior at Higher Concentrations**:
- As the concentration of these substances increases, they begin to aggregate or cluster together. This aggregation leads to the formation of larger structures known as micelles.

4. **Definition of Associated Colloids**:
- The substances that exhibit this behavior—where they act as normal electrolytes at low concentrations but form colloidal solutions at higher concentrations—are referred to as **associated colloids**.

5. **Examples of Associated Colloids**:
- Common examples of associated colloids include soaps and detergents. At higher concentrations, they form micelles, which are responsible for their colloidal behavior.

6. **Conclusion**:
- Therefore, the correct answer to the question is that the substances which behave as colloidal solutions at higher concentration are called **associated colloids**.

### Final Answer:
The substances which behave as colloidal solutions at higher concentration are called **associated colloids**.