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Describe the role of (i) NaCN in the extraction of gold from gold ore. (ii) SiO_(2) in the extraction of copper from copper matter. (iii) Iodine in the refining of zirconium. Write chemical equations for the involved reactions. |
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Answer» Solution :(i) ROLE of NaCN in the EXTRACTION of gold is to do leaching of gold ore in the pressence of air from which the gold is obtained LATER by replacement. `4Au(s)+8CN^(-)(aq)+2 H_(2)O+O_(2)(g) rightarrow 4[Au(CN)_(2)]^(-)+4 OH^(-)` (ii) `SiO_(2)` is added in copper matter to convert the remainingFeS, FeO to slag `FeO+Si O_(2) rightarrow underset(("slag")) (Fe Si O_(3))` (III) Iodine is heated with Zirconium to form a volatile-compound which on further HEATING decompose to give pure zirconium `Zr(impure)+2 I_(2)rightarrowZr I_(4)` `Zr I_(4) rightarrow Zr(pure)+2 I_(2)` |
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