Temporary hardness is cauesd due to the presence of-

Options

A. `CaSO_4`
B. `CaCl_2`
C. `CaCO_3`
D. `Ca(HCO_3)_(2)`

Answer

To solve the question regarding the cause of temporary hardness in water, we can follow these steps:

### Step-by-Step Solution:

1. **Understand Temporary Hardness**:
- Temporary hardness in water is primarily caused by the presence of bicarbonate minerals. These minerals can dissolve in water and lead to hardness.

2. **Identify the Options**:
- The options given are:
- A) CaSO4 (Calcium sulfate)
- B) CaCl2 (Calcium chloride)
- C) CaCO3 (Calcium carbonate)
- D) Ca(HCO3)2 (Calcium bicarbonate)

3. **Analyze Each Option**:
- **CaSO4**: This compound does not contribute to temporary hardness; it is a source of permanent hardness.
- **CaCl2**: This compound also does not cause temporary hardness; it is soluble but does not contain bicarbonate.
- **CaCO3**: While calcium carbonate can contribute to hardness, it is typically associated with permanent hardness when it is not in the bicarbonate form.
- **Ca(HCO3)2**: This is calcium bicarbonate, which is a bicarbonate mineral. It is known to cause temporary hardness in water.

4. **Conclusion**:
- Since temporary hardness is specifically caused by the presence of bicarbonate minerals, the correct answer is **D) Ca(HCO3)2 (Calcium bicarbonate)**.

### Final Answer:
The presence of **Ca(HCO3)2 (Calcium bicarbonate)** causes temporary hardness in water.

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