Heating a mixture of $\text{Ca(OH)}_2$ and $\text{NH}_4\text{Cl}$ gives gaseous products, which are then sent through solid $\text{CaO}$. One gaseous substance, W, is obtained. When a sample of W is allowed to react with $\text{Cl}_2(\text{g})$, two gases, X and Y, are formed. X is an element, whereas Y is acidic. Y reacts with W to form Z. Identify X and Z.
- A$X = \text{N}_2$, $Z = \text{CaCl}_2$
- B$X = \text{N}_2$, $Z = \text{NH}_4\text{Cl}$
- C$X = \text{O}_2$, $Z = \text{CaCl}_2$
- D$X = \text{O}_2$, $Z = \text{NH}_4\text{Cl}$