Which is true statement about `H_(2)O` :

Options

A. hardness can be removed by passing through ion exchange resin
B. its presence can be detected by anhydrous `CuSO_(4)`
C. it is amphoprotic
D. all are correct.

Answer

To determine which statements about water (H₂O) are true, we will analyze each statement provided in the question.

### Step-by-Step Solution:

1. **Understanding Hardness of Water**:
- Hardness in water is primarily due to the presence of dissolved minerals, particularly calcium (Ca²⁺) and magnesium (Mg²⁺) ions.
- These ions can be removed by passing the water through an ion exchange resin, which exchanges these hardness-causing ions for sodium ions (Na⁺).

**Conclusion**: The first statement is true.

2. **Detection of Water Hardness**:
- Anhydrous copper(II) sulfate (CuSO₄) is a common desiccant that can absorb moisture from the environment.
- When water is present, the anhydrous form turns blue, indicating the presence of moisture (water).

**Conclusion**: The second statement is true.

3. **Amphoteric Nature of Water**:
- Water is considered amphoteric because it can act as both an acid and a base.
- As a Lewis base, water can donate a lone pair of electrons, while as a Brønsted acid, it can donate a proton (H⁺).

**Conclusion**: The third statement is true.

4. **Final Conclusion**:
- Since all the statements regarding water are true, the correct answer is that all of the above statements are correct.

### Answer:
All of the above statements about water (H₂O) are true.

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