Sodium zeolite is_____.

Explanation

**Step-by-Step Solution:**

1. **Definition of Sodium Zeolite**:
Sodium zeolite is a type of zeolite that is primarily composed of sodium, aluminum, and silicon. It is a hydrated silicate mineral.

2. **Chemical Formula**:
The chemical formula for sodium zeolite can be expressed as Na2Al2Si2O8·xH2O, where 'x' represents the number of water molecules associated with the compound. For simplicity, it is often referred to as Na2Z.

3. **Function of Sodium Zeolite**:
Sodium zeolite is used to remove both temporary and permanent hardness from water. Temporary hardness is mainly caused by the presence of bicarbonates of calcium and magnesium, while permanent hardness is due to chlorides and sulfates of these metals.

4. **Mechanism of Action**:
The removal of hardness occurs through a process called cation exchange. When sodium zeolite is added to hard water, it exchanges sodium ions (Na+) for calcium (Ca²+) or magnesium (Mg²+) ions present in the water.

5. **Reaction Process**:
The reaction can be summarized as follows:
\[ \text{Na}_2\text{Z} + \text{Ca}^{2+} \text{(or Mg}^{2+}\text{)} \rightarrow \text{CaZ (or MgZ)} + 2\text{Na}^+ \]
This results in the formation of a precipitate (CaZ or MgZ), which can be removed from the water.

6. **Regeneration of Sodium Zeolite**:
After the cation exchange, the precipitate can be treated with a brine solution (a concentrated salt solution) to regenerate the sodium zeolite, allowing it to be reused for further treatment of hard water.

7. **Conclusion**:
Sodium zeolite is an effective agent for softening water by removing both temporary and permanent hardness through cation exchange and can be regenerated for repeated use.

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