REDOX & Electrochemistry - LSU Chemistry
REDOX 12c) Na 2 S 2 O 3 (aq) + NaOCl(s) NaCl(aq) + Na 2 S 4 O 6 (aq)(acidic)d) Au(s) + CN − (aq) + O 2 (g) Au(CN) − 4 (aq) + OH − (aq)(basic)
REDOX 13Electrochemical/Voltaic/Galvanic CellConsider the reaction of Zn(s) and Cu 2+ (aq):Zn(s) + Cu 2+ (aq)Zn 2+ (aq) + Cu(s)This reaction involves the transfer of 2 e- betweenthe Zn(s) and Cu 2+ . The Cu 2+ oxidizes the Zn, andis in turn reduced to form metallic Cu, while the Znmetal dissolves into solution as Zn 2+ .This reaction is spontaneous with a ΔGº = − 212kJ/mol. Mixing Zn(s) and Cu 2+ together in abeaker causes a spontaneous reaction that gives offall the energy as heat, warming the solution.The transferring of the electrons between the Znand Cu 2+ , however, can accomplish much moreuseful work if we can figure out a way to get the e-to flow through a wire as electricity, where the workrepresented by −ΔGº (free energy) can now be usedas electrical work.