An arsenious sulphide sol carries a negative charge the maximum precipitating power fo this sol is possessed by

Options

A. `K_(2)SO_(4)`
B. `CaCl_(2)`
C. `Na_(2)PO_(4)`
D. `AlCl_(3)`

Answer

To solve the question regarding the maximum precipitating power of an arsenious sulfide sol that carries a negative charge, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Charge of the Sol**:
- The question states that arsenious sulfide sol carries a negative charge. This means that the particles in the sol are negatively charged.

2. **Coagulation of Colloids**:
- Colloidal particles can be coagulated or precipitated by the addition of ions that carry an opposite charge. Since the sol is negatively charged, it can be coagulated by positive ions.

3. **Identifying the Precipitating Ions**:
- We need to look at the options provided (K2SO4, CaCl2, Na2Pa4, and AlCl3) and identify which of these contains positive ions that can precipitate the negatively charged arsenious sulfide sol.

4. **Determining the Valency of Cations**:
- The effectiveness of a cation in precipitating a negatively charged sol is related to its valency. The higher the valency of the cation, the greater its power to cause precipitation.
- Let's analyze the cations in the given compounds:
- K2SO4: Contains K⁺ (valency +1)
- CaCl2: Contains Ca²⁺ (valency +2)
- Na2Pa4: Contains Na⁺ (valency +1)
- AlCl3: Contains Al³⁺ (valency +3)

5. **Comparing the Valencies**:
- Among the cations listed, Al³⁺ has the highest valency of +3. Therefore, it will have the maximum precipitating power.

6. **Conclusion**:
- Based on the analysis, the cation with the highest valency, which is Al³⁺ from AlCl3, will possess the maximum precipitating power for the negatively charged arsenious sulfide sol.

### Final Answer:
- The maximum precipitating power for the arsenious sulfide sol is possessed by **AlCl3**.

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