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Copper can be extracted by hydrometallurgy but not zinc. Explain? |
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Answer» SOLUTION :The `E^(ɵ)` of zinc `((ZN^(2+))/(Zn)=-0.76V)` or iron `((Fe^(2+))/(Fe)=-0.44V)` is less than that of copper `((Cu^(2+))/(Cu)=+0.34V)` and hence both zinc and iron can displace copper from solution of `Cu^(2+)` ions. Although zinc is a stronger reducing agent than iron, yet iron scrap is chiefly used in hydrometallurgy of copper because it is much cheaper than Zinc. `Fe+Cu^(2+)toFe^(2+)+Cu_(s)` In CONTRAST, to replace zinc from solution of `Zn^(2+)` ions, a more reactive METAL than zinc is required, i.e., Al or Ca. But all these METALS react with water `(2H_2O+2e^(ɵ)toH_(2(g))+2overset(ɵ)(O)H_(aq):E^@-0.83V)` Forming their corresponding ions with the evolutionsof hydrogen gas. Although Al, Mg etc. Cannot be used to displace zinc from solution of `ZN^(2+)` ions. Thus, copper, can be extracted by hydrometallurgy but not zinc. |
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