Factor influencing the degree of ionization of a weak electrolyte is :

Options

A. dilution
B. temperature
C. presence of other ions
D. nature of solvent

Answer

To determine the factors influencing the degree of ionization of a weak electrolyte, we can follow these steps:

### Step 1: Understanding Weak Electrolytes
A weak electrolyte is a substance that partially ionizes in solution. For example, consider a weak electrolyte AB that dissociates into A⁺ and B⁻ ions.

### Step 2: Applying Ostwald's Dilution Law
According to Ostwald's dilution law, the degree of ionization (α) of a weak electrolyte can be expressed in relation to its concentration (C) and its dissociation constant (K_a). The equation is given by:

\[ K_a = \frac{C \alpha^2}{1 - \alpha} \]

### Step 3: Simplifying the Equation
For weak electrolytes, the value of α is very small (α << 1). Therefore, we can approximate \(1 - \alpha \approx 1\). This simplifies the equation to:

\[ K_a \approx C \alpha^2 \]

From this, we can solve for α:

\[ \alpha = \sqrt{\frac{K_a}{C}} \]

### Step 4: Identifying Factors Affecting Degree of Ionization
From the equation α = √(K_a/C), we can identify the factors that influence the degree of ionization:

1. **Concentration (C)**: As the concentration of the electrolyte decreases (dilution), α increases. This means that increasing dilution leads to a higher degree of ionization.

2. **Temperature**: Increasing the temperature generally increases the kinetic energy of the molecules, which can lead to increased ionization. Thus, higher temperatures can enhance the degree of ionization.

3. **Presence of Other Ions**: The common ion effect states that the presence of a common ion in the solution decreases the degree of ionization of the weak electrolyte. This is because the equilibrium shifts to the left, reducing α.

4. **Nature of Solvent**: The dielectric constant of the solvent affects ionization. Solvents with a high dielectric constant can stabilize ions in solution, leading to an increased degree of ionization.

### Conclusion
The factors influencing the degree of ionization of a weak electrolyte are:
- Dilution (concentration)
- Temperature
- Presence of other ions (common ion effect)
- Nature of solvent (dielectric constant)