which of the following electrolyte will be most effective in coagulation of negative sol ?

Options

A. `KNO_(3)`
B. `K_(4)[fe(CN)_(6)]`
C. `Na_(3)PO_(4)`
D. `MgCl_(2)`

Answer

To determine which electrolyte is most effective in coagulating a negative sol, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding Coagulation**: Coagulation refers to the process where colloidal particles aggregate to form a larger particle, which can then settle out of the solution. For a negative sol, we need to add an electrolyte that provides positive ions.

2. **Hardy-Schulze Rule**: According to the Hardy-Schulze rule, the effectiveness of an electrolyte in coagulating a colloidal solution is directly related to the valency of the positive ion in the electrolyte. The higher the valency, the more effective the coagulation.

3. **Analyzing the Options**:
- **Option 1: KNO3**:
- K+ has a valency of +1.
- **Option 2: K4[Fe(CN)6]**:
- K+ has a valency of +1. The complex ion [Fe(CN)6]4- does not contribute to the positive charge.
- **Option 3: Na3PO4**:
- Na+ has a valency of +1. The PO4^3- ion does not contribute to the positive charge.
- **Option 4: MgCl2**:
- Mg2+ has a valency of +2. Cl- ions do not contribute to the positive charge.

4. **Comparing the Valencies**:
- KNO3: +1
- K4[Fe(CN)6]: +1
- Na3PO4: +1
- MgCl2: +2

5. **Conclusion**: Since MgCl2 has the highest positive charge (+2), it will be the most effective electrolyte for coagulating a negative sol.

### Final Answer:
The most effective electrolyte in coagulating a negative sol is **MgCl2**.

---