Which of the following sols is negatively charged?

Options

A. Ferric hydroxide
B. Aluminium hydroxide
C. Aresenious sulphide
D. Silver iodide in silver nitrate solution

Answer

To determine which of the following sols is negatively charged, we need to understand the general characteristics of sols and their charge properties.

### Step-by-Step Solution:

1. **Understanding Sols**:
- A sol is a colloidal suspension of solid particles in a liquid. These sols can be positively or negatively charged depending on the nature of the dispersed phase.

2. **Classification of Sols**:
- Generally, metal hydroxides are known to form positively charged sols. This means that when metal ions (like Fe³⁺ or Al³⁺) are present in a hydroxide form, they tend to carry a positive charge.
- On the other hand, metal sulfides are typically negatively charged. This means that when metal ions are combined with sulfide ions (S²⁻), they tend to form negatively charged sols.

3. **Analyzing the Options**:
- **Ferric Hydroxide (Fe(OH)₃)**: This is a metal hydroxide and will be positively charged.
- **Aluminium Hydroxide (Al(OH)₃)**: This is also a metal hydroxide and will be positively charged.
- **Arsenous Sulfide (As₂S₃)**: This is a metal sulfide and will be negatively charged.
- **Silver Iodide (AgI)**: This is a salt formed from a metal and a halogen, and in a silver nitrate solution, it will behave as a positively charged sol due to the presence of Ag⁺ ions.

4. **Conclusion**:
- From the analysis, we can conclude that the only negatively charged sol among the given options is **Arsenous Sulfide (As₂S₃)**.

### Final Answer:
The negatively charged sol is **Arsenous Sulfide (As₂S₃)**.

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