InterviewSolution
Saved Bookmarks
InterviewSolution
| 1. |
Whatshouldbetheconsiderations duringtheextraction of metalsbyelectrochemical method ? |
|
Answer» SOLUTION :Duringextractionofmetalsbyelectrochemical method,the following twopoints mustbeconsideredtothat properprecautions canbetaken: (i)Reactivityofofmetals.If the metalsarequitereactiveand are expectedto reactwithwater , i.e,Na,Ca, Al,ETC. thenthemetalsshouldbeextractedbyelectrolysisof theirpurifiedmoltenoresratherthan theiraqueoussolutions. Forexample,Al isextractedbyelectrolysis of moltenalumina. (ii) SUITABILITY ofelectrodes. Theelectrodesselected shouldnotreactwiththeproductsof electrolysis. IFAT all theyreact,thentheelectrodesmustbemade upofametarialwhich isquite cheap sinceetheirperiodicreplacement shouldnotincrease thecostoftheprocess. Forexample, in theelectrolysis of alumina,` O_ 2`isliberatedatthe ANODE.IfFe orAl is madeastheanode, itwillbeattackedby` O_2`forming`Fe_2O_ 3orAl_2O _ 3`. As aresult, theanode will beeatenaway.Instead ofFeandAl,the anodesofcarbonarepreferredbecausecarbonis muchcheaperthanFeorAl. Thus,electrolysisof` Al_ 2O_3`is carriedout inanelectrolytictank usingcarbonas anode. |
|