Collidal dispersion have been classified into different types depending upon the physical state of the dispersed phases and the dispersion medium. They are prepared in the industry or in the laboratory by a number of methods and then purified. The protective action of lyophilic colloids was studied by Zsigmondy and he introduced a term called gold number.
Which of the following will have maximum flocculation value for aresnic sulphide sol?

Options

A. `BaCl_(2)`
B. `NaCl`
C. `KCl`
D. `AlCl_(3)`

Explanation

To determine which of the given substances has the maximum flocculation value for arsenic sulfide sol (As₂S₃), we need to understand the concept of flocculation and how it relates to the charge and valency of ions.

### Step-by-Step Solution:

1. **Understanding Flocculation**:
Flocculation is the process where fine particulates are agglomerated into a floc. In colloidal systems, the stability of the colloid can be disrupted by the addition of electrolytes, which can lead to coagulation or flocculation of the sol.

2. **Identifying the Charge of the Colloid**:
Arsenic sulfide (As₂S₃) is a negatively charged colloid. To flocculate this negatively charged sol, we need to add cations (positively charged ions).

3. **Valency of Cations**:
The coagulation power of cations is directly related to their valency. The higher the valency of the cation, the greater its ability to neutralize the charge of the colloid and cause flocculation.

4. **List of Cations and Their Valencies**:
- **Aluminium (Al³⁺)**: Valency = 3
- **Barium (Ba²⁺)**: Valency = 2
- **Potassium (K⁺)**: Valency = 1
- **Sodium (Na⁺)**: Valency = 1

5. **Order of Coagulation Power**:
The coagulation power of the cations decreases in the following order based on their valency:
- Al³⁺ > Ba²⁺ > K⁺ = Na⁺

6. **Flocculation Values in Millimoles**:
- Aluminium (Al³⁺): 0.093 mmoles
- Barium (Ba²⁺): 0.69 mmoles
- Potassium (K⁺): 50 mmoles
- Sodium (Na⁺): 51 mmoles

7. **Conclusion**:
Since sodium (Na⁺) has the highest flocculation value (51 mmoles) among the given options, it will cause the maximum flocculation of arsenic sulfide sol.

### Final Answer:
The substance with the maximum flocculation value for arsenic sulfide sol is **Sodium Chloride (NaCl)**.