Which of the following electrolytes will have maximum coagulating value for `Ag//Ag^(+)` sol?

Options

A. `Na_(2)S`
B. `Na_(2)PO_(4)`
C. `Na_(2)SO_(4)`
D. `NaCl`

Answer

To determine which electrolyte has the maximum coagulating value for the `Ag//Ag^(+)` sol, we can follow these steps:

### Step 1: Understand the Coagulation Process
Coagulation is the process where colloidal particles aggregate to form a larger particle. The coagulating power of an electrolyte is influenced by its charge. According to Hardy-Schulze rule, the coagulating power of an electrolyte increases with the charge of the ions.

### Step 2: Identify the Electrolytes
The electrolytes given are:
1. Na2S
2. Na3PO4
3. Na2SO4
4. NaCl

### Step 3: Dissociate the Electrolytes
Next, we need to dissociate each electrolyte into its constituent ions:
1. **Na2S** → 2 Na⁺ + S²⁻
2. **Na3PO4** → 3 Na⁺ + PO4³⁻
3. **Na2SO4** → 2 Na⁺ + SO4²⁻
4. **NaCl** → Na⁺ + Cl⁻

### Step 4: Analyze the Charges of the Anions
Now, we analyze the charges of the anions produced from each electrolyte:
1. S²⁻ has a charge of -2.
2. PO4³⁻ has a charge of -3.
3. SO4²⁻ has a charge of -2.
4. Cl⁻ has a charge of -1.

### Step 5: Apply Hardy-Schulze Rule
According to Hardy-Schulze rule, the coagulating power is directly related to the charge of the anion. The higher the negative charge, the greater the coagulating power:
- S²⁻ (charge -2)
- PO4³⁻ (charge -3)
- SO4²⁻ (charge -2)
- Cl⁻ (charge -1)

### Step 6: Conclusion
Among the anions, PO4³⁻ has the highest negative charge (-3), which means it will have the maximum coagulating power for the `Ag//Ag^(+)` sol.

Thus, the electrolyte with the maximum coagulating value for `Ag//Ag^(+)` sol is **Na3PO4**.

### Final Answer
**Na3PO4**

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