An AgI sol carries a negative charge. The maximum precipitating power is possessed by which of these electrolytes?

Options

A. `K_(2)SO_(4)`
B. `CaCI_(2)`
C. `Na_(3)PO_(4)`
D. `AICI_(3)`

Answer

To determine which electrolyte possesses the maximum precipitating power for an AgI sol that carries a negative charge, we can follow these steps:

### Step-by-Step Solution:

1. **Understanding the Charge of the Sol**:
- AgI sol carries a negative charge. This means that the particles in the sol are negatively charged.

2. **Coagulation Process**:
- For a negatively charged sol to coagulate (or precipitate), a positively charged ion (cation) is required to neutralize the negative charge. This neutralization allows the particles to come together and form larger aggregates, leading to precipitation.

3. **Identifying the Cations**:
- We need to consider the cations present in the given electrolytes. The options provided typically include:
- K+ (Potassium)
- Ca2+ (Calcium)
- Na+ (Sodium)
- Al3+ (Aluminum)

4. **Applying Hardy's Rule**:
- According to Hardy's rule, the coagulating power of a cation is directly related to its charge. The greater the charge on the cation, the more effective it will be in neutralizing the negative charge of the sol and facilitating coagulation.

5. **Comparing the Cations**:
- K+ has a charge of +1.
- Na+ has a charge of +1.
- Ca2+ has a charge of +2.
- Al3+ has a charge of +3.
- Among these, Al3+ has the highest charge.

6. **Conclusion**:
- Since Al3+ has the highest charge, it will possess the maximum precipitating power for the negatively charged AgI sol. Therefore, the correct answer is **Al3+**.

### Final Answer:
The electrolyte that possesses the maximum precipitating power for an AgI sol carrying a negative charge is **Al3+**.