Substances which behave as normal electrolytes in solution at low concentration and exhibit colloidal properties at higher concentration are called

Options

A. lyophilic colloids
B. lyophobic colloids
C. macromolecular colloids
D. associated colloids.

Explanation

To solve the question, we need to identify the type of substances that behave as normal electrolytes at low concentrations and exhibit colloidal properties at higher concentrations. Let's break down the solution step by step:

### Step 1: Understand the Definitions
We need to understand the definitions of the four types of colloids provided in the options:
1. **Lyophilic Colloids**: These are liquid-loving colloids that are stable and have a strong attraction between the colloidal particles and the solvent.
2. **Lyophobic Colloids**: These are liquid-fearing colloids that have a weak attraction between the colloidal particles and the solvent, making them less stable.
3. **Macromolecular Colloids**: These colloids form solutions with suitable solvents and are generally large molecules.
4. **Associated Colloids**: These colloids behave as normal electrolytes at low concentrations and exhibit colloidal properties at higher concentrations due to the formation of aggregates (micelles).

### Step 2: Analyze the Question
The question specifically asks for substances that:
- Behave as normal electrolytes in solution at low concentration.
- Exhibit colloidal properties at higher concentration due to the formation of aggregates.

### Step 3: Identify the Correct Option
From our analysis:
- **Lyophilic and Lyophobic Colloids** do not fit the criteria since they do not transition from electrolyte behavior to colloidal properties based on concentration.
- **Macromolecular Colloids** do not specifically describe the behavior at different concentrations.
- **Associated Colloids** fit the description perfectly as they behave as normal electrolytes at low concentrations and form micelles (aggregates) at higher concentrations.

### Conclusion
The correct answer is **Associated Colloids**.

### Final Answer
**Associated Colloids** (Option 4) are the substances that behave as normal electrolytes in solution at low concentration and exhibit colloidal properties at higher concentration.

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