Which has minimum solubility

Options

A. `Br_(2)S_(3)`
B. `Ag_(2)S`
C. CoS
D. PbS

Explanation

To determine which compound has the minimum solubility, we can follow these steps:

### Step 1: Understand the Concept of Solubility
Solubility refers to the ability of a substance (solute) to dissolve in a solvent. According to Faizan's law, the solubility of ionic compounds is inversely related to the polarization of the ions involved.

### Step 2: Analyze Polarization
Polarization is influenced by the charge and size of the ions. Higher charge and smaller size of the ions lead to greater polarization, which in turn decreases solubility.

### Step 3: Identify the Compounds
The compounds given in the question are:
1. Br2S3 (Bromine sulfide)
2. Ag2S (Silver sulfide)
3. COS (Carbonyl sulfide)
4. PbS (Lead sulfide)

### Step 4: Classify the Compounds
- **Br2S3**: This compound is non-polar due to the symmetrical arrangement of bromine and sulfur atoms, leading to no significant dipole moment.
- **Ag2S**: This is a polar compound because it consists of silver and sulfur, which have a significant difference in electronegativity.
- **COS**: Carbonyl sulfide is also polar due to the difference in electronegativity between carbon and sulfur, creating a dipole moment.
- **PbS**: Lead sulfide is polar as well, with lead and sulfur having a notable difference in electronegativity.

### Step 5: Compare Solubility
Since Br2S3 is non-polar, it will have low solubility in polar solvents (like water). On the other hand, Ag2S, COS, and PbS are polar and will have comparatively higher solubility due to their ionic nature and the ability to interact with polar solvents.

### Conclusion
Based on the analysis, **Br2S3** has the minimum solubility among the given compounds.

### Final Answer
The compound with minimum solubility is **Br2S3**.

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