General Principles and Processes of Isolation of Elements - Result Question 14
####14. Sulphide ores of metals are usually concentrated by froth flotation process. Which one of the following sulphide ores offer an exception and concentrated by chemical leaching? [2007]
(a) Galena
(b) Copper pyrite
(c) Sphalerite
(d) Argentite
Topic 3: Purification and Uses of Metals
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Solution:
- (d) Leaching is the selective dissolution of the desired mineral leaving behind the impurities in a suitable dissolving agent, e.g. Argentitie or Silver glance, $Ag_2 S$ is an ore of silver. Silver is extracted from argentite by the mac-Arthur and Forest process (leaching process).
$Ag_2 S+4 NaCN \to 2 Na[Ag(CN)_2]+Na_2 S$
