Coppercan beextracted byhydrometallurgybut notzinc. Explain.

1.	Coppercan beextracted byhydrometallurgybut notzinc. Explain.
Answer» SOLUTION : The` E^(@)`of zinc `(Zn^(2+)//Zn =- 076V) `oriron` (Fe^( 2 + )//Fe= - 044V )`islower thanthatofcopper` (CU^( 2 +) //Cu =+ 0 * 34V) `and hencebothzinc andFe,can displaceCu from solutionsof` Cu^( 2 +) `ions . Although zincisastrongerreducingagentthaniron,yet ironscrapischiefly used in hydrometallurgyofcopperbecauseitis muchcheaperthanzinc. `""Fe (s)+Cu^( 2+) (aq)to Fe^(2+) (aq)+Cu (s)` Incontrast,todisplacezinc from solutionof `Zn ^( 2 +) ` ions, weneeda morereactivemetalthan it, i.e., ` Al( E ^(@)""_(Al^(3 + )//Al) =- 166V), Mg (E ^(@)""_(Mg^(2 + )//Mg)= -237V)`, `Ca (E^(@)""_(Ca^(2+)//Ca) =- 287V), K(E ^(@)""_(K^(+)//K) =- 293V)`,etc. Butall thesemetalsreact withwater `[ 2 H_2 O+2 e ^(-) toH_ 2 (g)+2O H^( -) (aq) ,E ^(@) =-0 *83 V ] `formingtheircorrespondingionswiththe evolutionof`H_2`gas. Thus, Al, Mg, etc.,cannotbeusedto displacezinc fromsolution of` Zn^(2+)`ions. Thus,coppercan beextracted by hydrometallurgy but notzinc.

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