Which of the following is/are not true for lyophilic colloid ?

Options

A. These are prepared by special indirect methods.
B. The particles must travel towards the anode or cathode under the influence of an electric field.
C. These are called on intrinsic colloid
D. Small quantity of electrolyte is sufficient to cause precipitation of these.

Answer

To determine which statements about lyophilic colloids are not true, let's analyze each option step by step.

### Step 1: Understand the Definition of Lyophilic Colloids
Lyophilic colloids, also known as intrinsic colloids, consist of a dispersed phase that has a strong affinity for the dispersion medium. This strong interaction allows them to be stable and easily prepared.

### Step 2: Analyze Each Statement
1. **Option A: Those are prepared by special indirect methods.**
- **Analysis**: This statement is incorrect. Lyophilic colloids can be prepared by direct mixing or heating of the dispersed phase and the dispersion medium. Therefore, they do not require special indirect methods for preparation.

2. **Option B: The particles must travel towards the anode or cathode under the influence of an electric field.**
- **Analysis**: This statement is true. The particles in lyophilic colloids can migrate towards either the anode or cathode when an electric field is applied.

3. **Option C: Those are called intrinsic colloids.**
- **Analysis**: This statement is true. Lyophilic colloids are indeed referred to as intrinsic colloids due to their strong affinity for the dispersion medium.

4. **Option D: Small quantity of electrolyte is sufficient to cause precipitation of this.**
- **Analysis**: This statement is incorrect. Lyophilic colloids are stable and do not easily precipitate with the addition of small quantities of electrolytes. This characteristic is more typical of lyophobic colloids.

### Step 3: Conclusion
Based on the analysis:
- The incorrect statements regarding lyophilic colloids are **Option A** and **Option D**.

### Final Answer
The statements that are not true for lyophilic colloids are:
- **A**: Those are prepared by special indirect methods.
- **D**: Small quantity of electrolyte is sufficient to cause precipitation of this.

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