The molar conductivity of strong electrolyte

Options

A. Increases on dilution slightly
B. Does not change on dilution
C. Decreases on dilution
D. Depends on density of electrolyte itself

Answer

To solve the question regarding the molar conductivity of a strong electrolyte, we will analyze the options provided and apply the relevant concepts from electrochemistry.

### Step-by-Step Solution:

1. **Understanding Molar Conductivity**:
Molar conductivity (Λ) is defined as the conductivity (κ) of an electrolyte solution divided by its molar concentration (C). It is expressed as:
\[ Λ = \frac{κ}{C} \]
For strong electrolytes, which completely dissociate into ions in solution, the behavior of molar conductivity with dilution is crucial.

2. **Effect of Dilution on Strong Electrolytes**:
When a strong electrolyte is diluted, the concentration of ions in the solution decreases. However, the degree of ionization increases as the solution becomes more dilute. This is due to the increased distance between ions, which reduces ion-ion interactions and allows for greater mobility.

3. **Ionic Mobility**:
As the solution is diluted, the volume of the solution increases, and the ionic mobility of the ions also increases. Ionic mobility is the ability of ions to move through the solution under the influence of an electric field.

4. **Change in Molar Conductivity**:
The increase in ionic mobility leads to an increase in molar conductivity. Therefore, as the solution is diluted, the molar conductivity of a strong electrolyte increases slightly.

5. **Evaluating the Options**:
- **Option A**: Increases on dilution slightly - This is correct as explained above.
- **Option B**: Does not change on dilution - This is incorrect because molar conductivity does change.
- **Option C**: Decreases on dilution - This is incorrect for strong electrolytes as their molar conductivity increases.
- **Option D**: Depends on the density of the electrolyte itself - This is also incorrect as molar conductivity primarily depends on ion mobility and concentration, not density.

6. **Conclusion**:
Based on the analysis, the correct answer is **Option A**: "Increases on dilution slightly".