An albumin sol containing sodium chloride as an impurity can best be freed of this impurity by :

Options

A. Electrophoresis
B. Dialysis
C. Precipitation
D. Filtration

Explanation

To solve the problem of separating sodium chloride from an albumin solution, we can analyze the methods provided in the options. Here’s a step-by-step breakdown of the reasoning:

### Step 1: Understand the Components
- We have an albumin solution, which is a macromolecule (protein).
- Sodium chloride (NaCl) is a small ionic compound and is soluble in water.

### Step 2: Evaluate the Separation Methods
1. **Electrophoresis**:
- This method uses electric current to separate charged particles based on their mobility in an electric field.
- Since both albumin and sodium chloride are soluble in the solution, this method will not effectively separate them.
- **Conclusion**: Not suitable.

2. **Dialysis**:
- This technique involves the use of a semi-permeable membrane that allows smaller ions and molecules to pass through while retaining larger molecules.
- In this case, the semi-permeable membrane would allow sodium chloride to diffuse out of the albumin solution while retaining the larger albumin molecules.
- **Conclusion**: This is a suitable method for separating sodium chloride from albumin.

3. **Precipitation**:
- Precipitation involves adding a reagent to cause one component to become insoluble and form a solid, while the other remains in solution.
- Since both albumin and sodium chloride are soluble in the solution, this method is not applicable.
- **Conclusion**: Not suitable.

4. **Filtration**:
- Filtration is used when one component is insoluble in the solvent, allowing the solid to be separated from the liquid.
- Both albumin and sodium chloride are soluble in water, making this method ineffective.
- **Conclusion**: Not suitable.

### Step 3: Final Conclusion
Based on the analysis of the methods, **dialysis** is the best method to separate sodium chloride from an albumin solution.

### Final Answer:
The best method to free an albumin solution from sodium chloride impurity is **dialysis**.

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