be reduced to metal by carbon is a) PbO b) Al O c) ZnO d) FeO . Which of the metal is extracted by Hall-Heroult process? a) Al b) Ni c) Cu d) Zn . Which of the following statements, about the advantage of roasting of sulphide ore before reduction is not true?
a) Δ G f of sulphide is greater than those for CS and H S . b) Δ G r is negative for roasting of sulphide ore to oxide c) Roasting of the sulphide to its oxide is thermodynamically feasible. d) Carbon and hydrogen are suitable reducing agents for metal sulphides. XII U1 Metallurgy - XII U1 Metallurgy - - - - - .
Match items in column - I with the items of column – II and assign the correct code. Column-I Column-II Cyanide process (i) Ultrapure Ge B Froth floatation process (ii) Dressing of ZnS C Electrolytic reduction (iii) Extraction of Al D Zone refining (iv) Extraction of Au (v) Purification of Ni B C D (a) (i) (ii) (iii) (iv) (b) (iii) (iv) (v) (i) (c) (iv) (ii) (iii) (i) (d) (ii) (iii) (i) (v) . Wolframite ore is separated from tinstone by the process of a) Smelting b) Calcination c) Roasting d) Electromagnetic separation . Which one of the following is not feasible a) Zn(s) + Cu (aq) Cu(s) + Zn (aq) + + b) Cu(s) + Zn (aq) Zn(s) + Cu (aq) + + c) Cu(s) + 2Ag (aq) 2Ag(s) + Cu (aq) + d) Fe(s) + Cu (aq) Cu(s) + Fe (aq) + + .
Electrochemical process is used to extract a) Iron b) Lead c) Sodium d) silver . Flux is a substance which is used to convert a) Mineral into silicate b) Infusible impurities to soluble impurities c) Soluble impurities to infusible impurities d) All of these . Which one of the following ores is best concentrated by froth – floatation method? a) Magnetite b) Haematite c) Galena d) Cassiterite XII U1 Metallurgy - XII U1 Metallurgy -