Assertion : The values of colligative properties are of smaller order as compared to values shown by true solutions at same concentrations.
Reason : Colloidal particles show Brownian movement .

Options

A. If both assertion and reason are true and reason is the correct explanation of assertion.
B. If both assertion and reason are true but reason is not the correct explanation of assertion
C. If assertion is true but reason is false
D. if both assertion and reason are false

Explanation

To solve the question, we need to analyze the assertion and the reason provided.

**Assertion:** The values of colligative properties are of smaller order as compared to values shown by true solutions at the same concentrations.

**Reason:** Colloidal particles show Brownian movement.

### Step-by-Step Solution:

1. **Understanding Colligative Properties:**
- Colligative properties depend on the number of solute particles in a solution, not their identity. These properties include boiling point elevation, freezing point depression, vapor pressure lowering, and osmotic pressure.

2. **Comparing True Solutions and Colloidal Solutions:**
- True solutions consist of solute particles that are at the molecular or ionic level, which are typically much smaller than colloidal particles.
- Colloidal solutions contain larger particles (colloids) that are typically in the range of 1 nm to 1000 nm.

3. **Effect of Particle Size on Number of Particles:**
- In a given volume of solution, true solutions have a greater number of smaller particles compared to colloidal solutions, which have fewer larger particles.
- Since colligative properties depend on the number of particles, the fewer particles in colloidal solutions lead to smaller values of colligative properties compared to true solutions.

4. **Conclusion on Assertion:**
- The assertion is correct: the values of colligative properties are indeed smaller for colloidal solutions compared to true solutions at the same concentration because of the lower number of particles in colloidal solutions.

5. **Evaluating the Reason:**
- The reason states that colloidal particles show Brownian movement. While this is true, Brownian movement does not influence the calculation of colligative properties.
- Therefore, while the reason is correct, it does not explain the assertion.

6. **Final Evaluation:**
- Both the assertion and the reason are correct, but the reason does not provide a valid explanation for the assertion. Thus, the correct conclusion is that the assertion is true, the reason is true, but the reason does not explain the assertion.

### Final Answer:
- Assertion: True
- Reason: True, but does not explain the assertion.