Among the following, the INCORRECT statement about colloids is :

Options

A. They can scatter light
B. The osmotic pressure of a colloidal solution is of higher order than the true solution at the same concentration
C. The range of diameters of colloidal particles is between 1 and 1000 nm
D. They are larger than small molecules and have high molar mass

Explanation

To determine the incorrect statement about colloids, let's analyze the properties and characteristics of colloids step by step.

### Step 1: Understanding Colloids
Colloids are mixtures where microscopically dispersed insoluble particles of one substance are suspended in another substance. The size of the particles in a colloid typically ranges from 1 to 1000 nanometers (nm).

**Hint:** Recall the definition and size range of colloidal particles.

### Step 2: Types of Colloids
Colloids can be classified into different types based on the states of the dispersed phase and the dispersion medium:
- **Sol**: A colloidal solution with solid particles in a liquid.
- **Emulsion**: A colloidal solution of two liquids.
- **Foam**: Gas particles trapped in a liquid or solid.
- **Aerosol**: Small particles of liquid or solid dispersed in a gas.

**Hint:** Familiarize yourself with the different types of colloids and their characteristics.

### Step 3: Properties of Colloids
1. Colloids are heterogeneous mixtures.
2. The particles are too small to be seen with the naked eye.
3. They exhibit the Tyndall effect, scattering light and making the path of light visible.
4. The colligative properties of colloids are generally less pronounced than those of true solutions.
5. The osmotic pressure of a colloidal solution is of lower order than that of a true solution at the same concentration.

**Hint:** Pay attention to the properties of colloids, especially those related to their behavior in solutions.

### Step 4: Evaluating the Statements
Now, let's evaluate the statements provided in the question:
1. Colloids are heterogeneous mixtures.
2. The osmotic pressure of a colloidal solution is of higher order than that of a true solution at the same concentration. (This is the incorrect statement.)
3. The size of colloidal particles is between 1 and 1000 nm.
4. Colloidal particles are larger than small molecules and have high molar mass.

**Hint:** Identify which statement contradicts the known properties of colloids.

### Conclusion
The incorrect statement about colloids is: "The osmotic pressure of a colloidal solution is of higher order than that of a true solution at the same concentration." This statement is incorrect because the osmotic pressure of a colloidal solution is actually of lower order than that of a true solution at the same concentration.

**Final Answer:** The incorrect statement is option 2.