Hard water is impure due to presence of

Options

A. bicarbonates of calcium
B. chlorides of calcium
C. bicarbonates of magnesium
D. All of the above

Explanation

**Step-by-Step Solution:**

1. **Definition of Hard Water**: Hard water is defined as water that contains a high concentration of dissolved minerals, particularly calcium and magnesium ions.

2. **Components of Hard Water**: The primary impurities that contribute to water hardness include:
- Calcium ions (Ca²⁺)
- Magnesium ions (Mg²⁺)
- Bicarbonates (Ca(HCO₃)₂ and Mg(HCO₃)₂)
- Chlorides (CaCl₂ and MgCl₂)
- Sulfates (CaSO₄ and MgSO₄)

3. **Types of Hardness**:
- **Temporary Hardness**: Caused mainly by bicarbonates of calcium and magnesium, which can be removed by boiling.
- **Permanent Hardness**: Caused by chlorides and sulfates of calcium and magnesium, which cannot be removed by boiling.

4. **Impurities in Hard Water**: Given the options:
- Bicarbonate of calcium (Ca(HCO₃)₂) is present in hard water.
- Chloride of calcium (CaCl₂) is also present in hard water.
- Bicarbonate of magnesium (Mg(HCO₃)₂) is present in hard water as well.

5. **Conclusion**: Since all the mentioned substances (bicarbonate of calcium, chloride of calcium, and bicarbonate of magnesium) are present in hard water, it is correct to say that hard water is impure due to the presence of all of these impurities.

6. **Final Answer**: Therefore, the correct answer to the question is that hard water is impure due to the presence of all of the above options.

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