How many water molecules does hydrated calcium sulphate contain ?

Options

A. 5
B. 10
C. 7
D. 2

Explanation

To find out how many water molecules are present in hydrated calcium sulfate, we can follow these steps:

### Step-by-Step Solution:

1. **Identify the Compound**: The hydrated form of calcium sulfate is represented as CaSO₄·2H₂O. Here, "CaSO₄" is calcium sulfate, and "2H₂O" indicates the presence of water molecules.

2. **Understand the Notation**: The dot (·) in the formula indicates that the water molecules are associated with the calcium sulfate in a specific ratio. In this case, "2H₂O" means there are two water molecules for every formula unit of calcium sulfate.

3. **Count the Water Molecules**: From the formula CaSO₄·2H₂O, we can see that there are 2 water molecules (H₂O) associated with each unit of calcium sulfate.

4. **Conclusion**: Therefore, hydrated calcium sulfate contains **2 water molecules**.

### Final Answer:
Hydrated calcium sulfate contains **2 water molecules**.

---