The degree of dissociation (extent of ionization ) increases

Options

A. with the increase in concentration of solute
B. on addition of excenss water to solution
C. on increasing the temperature of solution
D. on stirring the solution vigorously

Answer

To solve the question regarding the degree of dissociation (extent of ionization) and its relationship with various factors, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Degree of Dissociation (α)**:
- The degree of dissociation (α) is defined as the fraction of the total number of moles of a solute that dissociates into ions.
- It can be expressed mathematically for acids as:
\[ \alpha = \sqrt{\frac{K_a}{C}} \]
where \( K_a \) is the acid dissociation constant and \( C \) is the concentration of the solution.

2. **Analyzing the Options**:
- We need to determine which conditions lead to an increase in the degree of dissociation (α).

3. **Option 1: Increase in Concentration of the Solute**:
- As concentration (C) increases, α decreases because they are inversely related.
- **Conclusion**: This option does not lead to an increase in α.

4. **Option 2: Addition of Excess Water to the Solution**:
- Adding excess water dilutes the solution, effectively reducing the concentration (C).
- As concentration decreases, α increases.
- **Conclusion**: This option leads to an increase in α.

5. **Option 3: Increasing Temperature**:
- Increasing temperature can affect the dissociation of weak acids and bases. For endothermic dissociation reactions, increasing temperature generally increases the degree of dissociation.
- Additionally, increasing temperature can lead to a decrease in effective concentration.
- **Conclusion**: This option also leads to an increase in α.

6. **Option 4: Stirring the Solution Vigorously**:
- Stirring can enhance the mixing of the solution but does not significantly affect the concentration of the solute or the degree of dissociation.
- **Conclusion**: This option does not lead to an increase in α.

7. **Final Conclusion**:
- The options that lead to an increase in the degree of dissociation are **Option 2 (Addition of Excess Water)** and **Option 3 (Increasing Temperature)**.

### Summary of Answers:
- The degree of dissociation increases with:
- **Option 2**: Addition of excess water to the solution.
- **Option 3**: Increasing temperature.