Name the compound used in Clark’s method to remove temporary hardness of water.

Answer

**Step-by-Step Solution:**

1. **Understanding Temporary Hardness of Water**: Temporary hardness of water is primarily caused by the presence of dissolved bicarbonate minerals, mainly calcium bicarbonate (Ca(HCO₃)₂) and magnesium bicarbonate (Mg(HCO₃)₂).

2. **Identifying the Method**: The Clark method is a common technique used to remove temporary hardness from water.

3. **Identifying the Compound Used**: The compound used in the Clark method is calcium hydroxide (Ca(OH)₂).

4. **Chemical Reaction**: When calcium hydroxide is added to water containing temporary hardness, it reacts with the calcium and magnesium bicarbonates present. The reaction can be represented as follows:
- For calcium bicarbonate:
\[ Ca(HCO₃)₂ + Ca(OH)₂ \rightarrow CaCO₃ + 2H₂O \]
- For magnesium bicarbonate:
\[ Mg(HCO₃)₂ + Ca(OH)₂ \rightarrow MgCO₃ + CaCO₃ + 2H₂O \]
In these reactions, calcium carbonate (CaCO₃) and magnesium carbonate (MgCO₃) are formed, which precipitate out of the solution, effectively removing the hardness.

5. **Conclusion**: Therefore, the compound used in Clark’s method to remove temporary hardness of water is calcium hydroxide (Ca(OH)₂).

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