Plaster of Paris (POP) is

Options

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

Explanation

**Step-by-Step Solution:**

1. **Identify the substance**: Plaster of Paris (POP) is a compound derived from gypsum.

2. **Chemical formula of gypsum**: The chemical formula for gypsum is \( \text{CaSO}_4 \cdot 2\text{H}_2\text{O} \). This indicates that gypsum contains calcium sulfate and two water molecules.

3. **Heating gypsum**: When gypsum is heated to about 373 Kelvin (approximately 100°C), it undergoes a dehydration process. This means that some of the water molecules are removed.

4. **Formation of Plaster of Paris**: Upon heating, gypsum loses one and a half water molecules. The resulting compound, Plaster of Paris, has the chemical formula \( \text{CaSO}_4 \cdot \frac{1}{2}\text{H}_2\text{O} \).

5. **Final chemical formula**: Therefore, the chemical formula for Plaster of Paris is \( \text{CaSO}_4 \cdot \frac{1}{2}\text{H}_2\text{O} \).

6. **Conclusion**: The correct answer from the options provided is \( \text{CaSO}_4 \cdot \frac{1}{2}\text{H}_2\text{O} \).