Question

In Van- Arkel method, if ${I_2}$ is introduced at 1700K over impure metal, the product will be:
A.Iodide of the metal
B.No reaction takes place
C.Impurities react with iodine
D.None of them

Answer 1

Hint: The Van-Arkel is used for the purification of the impure metals, and is based on the thermal decomposition of the metal components. By this method impure metals are refined and Titanium is purified through this method.
This method is used for the purification of the ductile metal Zirconium and is the first commercial process used.

Complete step by step answer:
In the electrolytic refining of the Titanium metal, the impure metal is heated with the Iodine at a temperature of 1700 K and the impurities of the metals do not react with the iodine added in the solution for the purification of the metal, and the volatile titanium tetra iodide is formed. When these volatile vapours are passed over the heated tungsten metal, these vapours decompose and the pure metal is obtained in this reaction, Later on the iodine added in the solution is reused.
Crystal bar process is used for the purification of this metal, and can be performed using any number of metals using whichever halogen or combination of the halogens is most appropriate for that sort of mechanism. The metal iodide is formed which can be given by the following reaction:
$2M + {I_2} \to 2MI$
Where M is the impure metal.
The iodide of the metal is formed when I2 is introduced at 1700K over impure metal, thus the option (A) is the correct answer.

Note:
There are series of reactions which are used for the purification of the metal; these are extraction of the metals, concentration of the ore and the purification of the metal under examination which is to be purified.