Pick out incorrect statement

Options

A. Colloidal sols are heterogeneous
B. Colloids carry + ve or - ve charge
C. Colloidal sols show Tyndall effect
D. The size range of colloidal particles `10 - 2000Å`

Answer

To solve the question of identifying the incorrect statement regarding colloidal sols, we will analyze each option step by step.

### Step-by-Step Solution:

1. **Analyze Option A**:
- Statement: "Colloidal sols are heterogeneous."
- Explanation: Colloidal sols consist of dispersed particles in a medium. While they may appear homogeneous to the naked eye, they are heterogeneous at the microscopic level because they contain distinct phases (dispersed phase and dispersion medium).
- Conclusion: This statement is **correct**.

2. **Analyze Option B**:
- Statement: "Colloids carry positive and negative charge."
- Explanation: Colloids can indeed carry either positive or negative charges depending on the nature of the dispersed particles. This is a fundamental property of colloids.
- Conclusion: This statement is **correct**.

3. **Analyze Option C**:
- Statement: "Colloidal sols show Tyndall effect."
- Explanation: The Tyndall effect refers to the scattering of light by small particles in a colloid. Since colloidal particles are of a size that can scatter light, this statement is also true.
- Conclusion: This statement is **correct**.

4. **Analyze Option D**:
- Statement: "The size range of colloidal particles is 10 to 2000 angstrom."
- Explanation: The typical size range for colloidal particles is actually from 10 to 1000 angstroms, not 2000 angstroms. Therefore, this statement is incorrect.
- Conclusion: This statement is **incorrect**.

### Final Answer:
The incorrect statement is **Option D**.