Which among the following sulphates is insoluble in water ?

Options

A. `CuSO_(4)`
B. `CdSO_(4)`
C. `PbSO_(4)`
D. `Bi_(2)(SO_(4))_(3)`

Answer

To determine which among the given sulfates is insoluble in water, we need to analyze the solubility of each sulfate mentioned: CuSO4 (copper sulfate), cadmium sulfate, lead sulfate, and bismuth sulfate.

### Step-by-Step Solution:

1. **Identify the Sulfates**:
We have four sulfates to consider:
- CuSO4 (Copper sulfate)
- CdSO4 (Cadmium sulfate)
- PbSO4 (Lead sulfate)
- BiSO4 (Bismuth sulfate)

2. **Understand Solubility Rules**:
Generally, most sulfates are soluble in water, but there are exceptions. The common exceptions include sulfates of barium (BaSO4), lead (PbSO4), and calcium (CaSO4).

3. **Analyze Each Sulfate**:
- **CuSO4**: This sulfate is soluble in water.
- **CdSO4**: This sulfate is also soluble in water.
- **PbSO4**: Lead sulfate is known to be insoluble in water due to its high lattice energy which is not compensated by the hydration energy provided by water.
- **BiSO4**: Bismuth sulfate is generally soluble in water.

4. **Determine the Insoluble Sulfate**:
Among the sulfates listed, lead sulfate (PbSO4) is the only one that is insoluble in water due to its high lattice energy.

5. **Conclusion**:
Therefore, the sulfate that is insoluble in water is **lead sulfate (PbSO4)**.

### Final Answer:
Lead sulfate (PbSO4) is insoluble in water.

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