A cell constant is generally found by measuring the conductivity of aqueous solution of

Options

A. `BaCl_(2)`
B. `KCl`
C. `NaCl`
D. `MgCl_(2)`

Explanation

To solve the question regarding the cell constant and the aqueous solution used for its measurement, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Cell Constant**: The cell constant (K) is a factor that relates the conductivity of a solution to the resistance measured in a conductivity cell. It is defined as the ratio of the distance between the electrodes to the area of the electrodes.

2. **Conductivity Measurement**: To determine the cell constant, we need to measure the conductivity (κ) of a solution. Conductivity is a measure of a solution's ability to conduct electric current, which depends on the concentration and mobility of ions in the solution.

3. **Choosing the Right Solution**: The question asks for the aqueous solution used to measure the cell constant. The most commonly used solution for this purpose is potassium chloride (KCl).

4. **Reason for Using KCl**:
- **Known Conductivity**: The conductivity of KCl is well-documented and known accurately at various concentrations and temperatures. This makes it a reliable standard for measurements.
- **Ionic Strength**: KCl is a strong electrolyte that dissociates completely in water, providing a consistent ionic strength which is essential for accurate conductivity measurements.

5. **Conclusion**: Based on the above reasoning, the correct answer to the question is that the cell constant is generally found by measuring the conductivity of an aqueous solution of KCl.

### Final Answer:
The cell constant is generally found by measuring the conductivity of an aqueous solution of **KCl** (option B).

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