Zone Refining

Q. Zone refining is used for the purification of

1. $Ge$
2. $Si$
3. $Ga$
4. $Se$

Q. When an impurity in a metal has a greater affinity towards oxygen and is more easily oxidized than the metal itself, then the metal is refined by:

1. Cupellation
2. Zone refining
3. Poling
4. Electrolytic process