`Yoverset(Delta,250^(@)C)rarrCaSO_(4).2H_(2)Ooverset(Delta,120^(@)C)rarrX.` X and Y are respectively :

Options

A. Plaster of paris, dead burnt plaster, calcium sulphide
B. dead burnt plaster, plaster of Paris, lime
C. Plaster of Pairs, dead burnt plaster, calcium sulphite
D. plaster of Paris, dead burnt plaster, calcium oxide (lime)

Answer

To solve the question, we need to identify the products Y and X from the given reactions involving gypsum (CaSO4·2H2O).

### Step-by-Step Solution:

1. **Identify the Initial Compound**:
The compound given is CaSO4·2H2O, which is known as gypsum.

2. **Heating Gypsum at 250°C**:
When gypsum (CaSO4·2H2O) is heated strongly at 250°C, it undergoes a decomposition reaction. The water of crystallization is lost, leading to the formation of calcium sulfate (CaSO4) and calcium oxide (CaO).
- **Reaction**:
\[ \text{CaSO}_4 \cdot 2\text{H}_2\text{O} \xrightarrow{\Delta, 250^\circ C} \text{CaSO}_4 + \text{CaO} \]
- **Product Y**: The products formed are CaSO4 (dead burnt plaster) and CaO (calcium oxide).

3. **Heating Gypsum at 120°C**:
Next, when gypsum is heated at a lower temperature of 120°C, it loses some of its water of crystallization but not all. This results in the formation of calcium sulfate with 1.2 water molecules, known as plaster of Paris (POP).
- **Reaction**:
\[ \text{CaSO}_4 \cdot 2\text{H}_2\text{O} \xrightarrow{\Delta, 120^\circ C} \text{CaSO}_4 \cdot 1.2\text{H}_2\text{O} \]
- **Product X**: The product formed is plaster of Paris (CaSO4·1.2H2O).

4. **Conclusion**:
Thus, we can summarize:
- **Product X**: Plaster of Paris (CaSO4·1.2H2O)
- **Product Y**: Dead burnt plaster (CaSO4) and Calcium Oxide (CaO)

### Final Answer:
- X is plaster of Paris (CaSO4·1.2H2O).
- Y is dead burnt plaster (CaSO4) and calcium oxide (CaO).