Select the correct option based on the statements below:
Assertion (A): Zirconium can be purified by the van Arkel method.
Reason (R): ZrI4 is volatile and decomposes at 1800 K.
1. Both (A) and (R) are true and (R) is the correct explanation of (A).
2. Both (A) and (R) are true but (R) is not the correct explanation of (A).
3. (A) is true but (R) is false.
4. (A) is false but (R) is true.

Hint: Zirconium can be purified by the van Arkel method

This method is very useful for removing all the oxygen and nitrogen present in the form of impurity in certain metals like Zr and Ti. The crude metal is heated in an evacuated vessel with iodine. The metal iodide being more covalent, volatilises:

Zr + 2I2 → ZrI4

The metal iodide is decomposed on a tungsten filament, electrically heated to about 1800K. The pure metal deposits on the filament.

ZrI4 → Zr + 2I2