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

Zone refining is a technique used primarily for which one of the following processes?

Which of the following statements are correct related to metallurgy?
$A$. In electrolytic refining of copper,pure $Cu$ is used as anode.
$B$. Zone refining is based on the principle that impurities are more soluble in the melt than in the solid state of the metal.
$C$. $TiI_4$ upon heating will give pure $Ti$.
$D$. Very pure $Zr$ may be obtained by galvanisation.
$E$. In copper smelting,hot air is used to convert to $CuSO_4$.
The correct answer is

Nitriding is a process of heating steel in an atmosphere of

Steel becomes soft and pliable by:

Describe a method for refining nickel.