Number of water molecules present in gypsum,dead burnt plaster and plaster of paris respectively are

Options

A. 2,0,0.5
B. 0.5,2,0
C. 2,0.5,0
D. 0,2,0.5

Answer

To determine the number of water molecules present in gypsum, dead burnt plaster, and plaster of Paris, we can follow these steps:

### Step 1: Identify the chemical formula of gypsum.
- Gypsum is chemically represented as **CaSO₄·2H₂O**. This indicates that there are **2 water molecules** associated with each formula unit of gypsum.

### Step 2: Identify the chemical formula of dead burnt plaster.
- Dead burnt plaster is essentially **anhydrous calcium sulfate**, represented as **CaSO₄**. Since it is anhydrous, it does not contain any water molecules. Therefore, the number of water molecules in dead burnt plaster is **0**.

### Step 3: Identify the chemical formula of plaster of Paris.
- Plaster of Paris is represented as **CaSO₄·(1/2)H₂O** or **CaSO₄·0.5H₂O**. This indicates that there is **0.5 water molecules** associated with each formula unit of plaster of Paris.

### Summary of the number of water molecules:
- **Gypsum**: 2 water molecules
- **Dead burnt plaster**: 0 water molecules
- **Plaster of Paris**: 0.5 water molecules

### Final Answer:
The number of water molecules present in gypsum, dead burnt plaster, and plaster of Paris respectively are **2, 0, and 0.5**.

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