(i) Indicate the principle behind the method used for the refining of zinc.
(ii) What is the role of silica in the extraction of copper ?
(iii) Which form of iron is the purest on commercial scale ?

(i) Indicate the principle behind the method for the refining of nickel. (ii) What is the role of dilute NaCN in the extraction of gold ? (iii) What is copper matte ?

(i) Name the method of refining of nickel (ii) What is the role of cryolite in the extraction of aluminium ? (iii) What is the role of limestone in the extraction of iron from its oxides ?

Why limestone is use to convert hematite to pig iron. What is the role of silica for the extraction of Cu.

(i) Name the method of refining to obtain silicon of high purity. (ii) What is the role of SiO_2 in the extraction of copper? (iii) What is the role of depressants in froth floatation process ?

(i) Name a method used for the refining of zirconium. (ii) What is the role of CO in the extraction of iron ? (iii) Reduction of metal oxide to metal becomes easier if the metal obtained is in the liquid state. Why ?