IMG_0001_NEW_0038 - Need electrolyte -+ molten salt...

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Electrolysis and Electroplating Electrolysis + metal plates cathode Mixture of ions: Gradually increase.voltage - which "plates out" first? Ag*+t-+Ag E :0.80V cu2*+2t+cu E:0.34Y Zn2* +?n- -+7a, E :4.76V More positive E = greater tendency to proceed spontaneously = Ag plares at lower voltages than Cu andZn Electrolysis of NaGl(s) Production of Na metal = can't have water present! Electrolyte : molten salt T.".'rfiaCl):8(X) "C T..r4(N{yC{lt:600'c llalf reactions: Anode: 2Ctr -->Ar+2e- E Cdode: Na*+e--+Na E :-1.36 V = -2.71Y Production of Aluminum Aluminum ore: Bauxite: AlrO, * other metal oxides Can't use aqueous solution of Al3* Al3*+3e-+Al E:-t.66V 4HrO + 2e' -> 2Hz+ 4OH- ,E :-{.83 V + water more easily reduced
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Unformatted text preview: Need electrolyte -+ molten salt T*atoe(AlzOr) :2050 "C T-"ftn s(Al2O3A.{a3AlF6) : 1000 'C Elccrodrr.f frrthil$ rcdr Csbd didi& dE ttF&9 Cd!s-li!.d imte*-Overall cell reaction: 2Al2A3+ 3C -+ 4Al + 3CO2 Electrolysis of NaCl(aq) Brine (aqueous NaCl) -+ Cl, and NaOH Electrolysis reactions : . Cathode reaction: water reduction 4HzO + 2{ -+ 2ll, + 4OH- E : --0.83 V . Sodium Chloride: In HrO : Na* and Cl-. Anode reaction: chloride oxidation 2Ctr-+Cl2+2{ E:-1.36V . Overall electrolysis reaction: 2Cf + 4HrO -+ Clr+ 211, + 4OH-Chlor-alkali Process: produces pure NaOH Replaced by membrane technologies (For environmental reasons !)...
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This note was uploaded on 12/27/2011 for the course CHEM 122 taught by Professor Williams during the Fall '10 term at Simon Fraser.

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