The method used for obtaining highly pure silicon,which is used as a semiconductor material,is:

During the refining of copper,the methane gas produced acts as a reducing agent. What is its specific role?

Which process of purification is represented by the following scheme?
$\text{Ti}_{\text{impure}} + 2I_2$ $\xrightarrow{250^{\circ}C} TiI_4$ $\xrightarrow{1400^{\circ}C} \text{Ti}_{\text{pure}} + 2I_2$

$Si$ and $Ge$ used for semiconductors are required to be of high purity and hence purified by:

Identify the statements which are not correct.
$a)$ Copper is refined by Van-Arkel method
$b)$ Zinc is refined by electrolysis method
$c)$ Zirconium is refined by distillation method

Nitriding is a process of heating steel in an atmosphere of