(i) Indicate the principle behind the method used for the refining of�

1.	(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 the iron is the purest form of commercial iron ?
Answer» (i) Zincis refined by electrolytic refining. (a) This method is based upon the phenomenon of electrolysis. (b) The crude metal is made anode whereas a thin sheet of pure metal is made cathode. (c) Electrolyte is the solution of some salt of metal. (ii) In the extraction of copper, silica (SiO₂) acts as'flux'. It reacts with FeO and removes it as slag (FeSiO₃). FeO + SiO₂ → FeSiO₃ (Flux) slag (iii) Wrought iron is the purest form of iron.

(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 the iron is the purest form of commercial iron ?

Answer»

(i) Zincis refined by electrolytic refining.

(a) This method is based upon the phenomenon of electrolysis.

(b) The crude metal is made anode whereas a thin sheet of pure metal is made cathode.

(ii) In the extraction of copper, silica (SiO₂) acts as'flux'. It reacts with FeO and removes it as slag (FeSiO₃).

FeO + SiO₂ → FeSiO₃

(Flux) slag

(iii) Wrought iron is the purest form of iron.