Question

A compound ‘X’ on heating at \(373 \, \text{K}\) loses water molecules and becomes ‘Y’. Substance ‘Y’ is used by doctors for supporting fractured bones in the right position.

1. Identify ‘X’ and ‘Y’.
2. How can we obtain ‘X’ from ‘Y’?

Answer 1

(i) Identification of X and Y:

Compound X is Gypsum (\( \text{CaSO}_4 \cdot 2\text{H}_2\text{O} \)), and compound Y is Plaster of Paris (\( \text{CaSO}_4 \cdot \frac{1}{2}\text{H}_2\text{O} \)). Plaster of Paris loses water molecules upon heating to form Gypsum. Gypsum is used as a support for fractured bones.

(ii) Obtaining X from Y:

Gypsum (\( \text{CaSO}_4 \cdot 2\text{H}_2\text{O} \)) can be converted back to Plaster of Paris (\( \text{CaSO}_4 \cdot \frac{1}{2}\text{H}_2\text{O} \)) by heating it at 373 K. This process removes some of the water molecules from Gypsum to form Plaster of Paris.