Which one is correct statement for zeolite ?

Options

A. They are alumino silicates
B. Hydrated zeolites are used as ion exchangers in hardening of soft water
C. ZSM - 5 is used to convert gasoline to alcohol
D. All of these

Answer

To determine the correct statement about zeolites, we need to analyze the properties and uses of zeolites based on the information provided.

### Step-by-Step Solution:

1. **Understanding Zeolites**:
- Zeolites are a group of silicate minerals that have a three-dimensional framework structure. They are composed of silicon (Si) and aluminum (Al) atoms, forming a network of silicate tetrahedra (SiO4) and alumina tetrahedra (AlO4).

2. **Identifying the Composition**:
- The basic unit of zeolites is the aluminosilicate, which means they contain both aluminum and silicon in their structure. This confirms that zeolites are indeed aluminosilicates.

3. **Evaluating the Statements**:
- **Statement A**: "They are aluminosilicates."
- This statement is correct because zeolites are indeed composed of aluminum and silicon.

- **Statement B**: "Hydrated zeolites are used as ion exchangers in hardening of soft water."
- This statement is incorrect. Zeolites are used to soften hard water by exchanging calcium and magnesium ions with sodium ions, not in hardening soft water.

- **Statement C**: "ZSM 5 is used to convert gasoline to alcohol."
- This statement is also incorrect. ZSM-5 is a type of zeolite used in the petrochemical industry, primarily for converting alcohols to gasoline, not the other way around.

4. **Conclusion**:
- Based on the evaluation, the only correct statement about zeolites is **Statement A**: "They are aluminosilicates."

### Final Answer:
The correct statement for zeolite is: **They are aluminosilicates.**