Which of the following is dead. Burnt plaster?

Options

A. `CaCO_(3)`
B. `CaSO_(4).(1)/(2)H_(2)O`
C. `CaSO_(4)2H_(2)O`
D. `CaSO_(4)`

Answer

To determine which of the given options is dead burnt plaster, we need to understand what dead burnt plaster is and how it is formed.

### Step-by-Step Solution:

1. **Understanding Plaster of Paris**:
- Plaster of Paris is chemically represented as \( \text{CaSO}_4 \cdot \frac{1}{2} \text{H}_2\text{O} \). It is formed by heating gypsum (calcium sulfate dihydrate, \( \text{CaSO}_4 \cdot 2\text{H}_2\text{O} \)) to remove water.

2. **Formation of Dead Burnt Plaster**:
- When plaster of Paris is heated further, it loses all its water content and transforms into anhydrous calcium sulfate, which is known as dead burnt plaster or simply dead plaster. The chemical formula for dead burnt plaster is \( \text{CaSO}_4 \).

3. **Identifying Dead Burnt Plaster**:
- Dead burnt plaster is characterized by the absence of water molecules. Therefore, we are looking for the anhydrous form of calcium sulfate, which is \( \text{CaSO}_4 \).

4. **Analyzing Options**:
- If the options provided include various forms of calcium sulfate, we need to identify which one is anhydrous.
- The options might include:
- \( \text{CaSO}_4 \cdot 2\text{H}_2\text{O} \) (Gypsum)
- \( \text{CaSO}_4 \cdot \frac{1}{2}\text{H}_2\text{O} \) (Plaster of Paris)
- \( \text{CaSO}_4 \) (Dead Burnt Plaster)
- Other hydrated forms of calcium sulfate.

5. **Conclusion**:
- The correct answer to the question "Which of the following is dead burnt plaster?" is \( \text{CaSO}_4 \) (anhydrous calcium sulfate).