Metals like copper, mercury and lead are obtained from their oxide ores by

Q. Metals which can be obtained by carbon reduction of their oxides are _________.

Q. In the extraction of copper from its sulphide ore, the metal finally obtained by the reduction of cuprous oxide with

Q. Aluminium and copper are extracted from their oxide and sulphide ores respectively. Which of the following is correct ?
I. Copper is extracted by the auto reduction of copper oxide by copper sulphide.
II. Aluminium cannot be obtained by chemical reduction due to its strong affinity for oxygen.
III. In electrometallurgy of $Al$, graphite is used as cathode to avoid reoxidation of $Al$ into $A{l}_2{O}_3$ by preventing formation of $O_2$.
IV. Sulphide ores of copper are difficult to be reduced than the oxide ores.

Q. Carbon reduction is not used to obtain certain metals from their ores because
1. Carbon cannot reduce certain oxides, sulphides, etc
2. It can react with the metals to form carbides
3. Temperatures required for the reduction are too high
4. It is expensive compared to the alternatives for some ores

Q. Lead obtained from galena ore (PbS) by air reduction or carbon reduction process contains base metal (Cu, Bi, As, Sn, Zn) as impurities. The removal of the impurity of Ag from the commercial lead is called: