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Rusting. PowerPoint Presentation

Rusting.

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Rusting.

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  1. Rusting.

  2. Rusting and the redox cycle Reduction Extraction Metal oxide Fe3+ Metal Fe Corrosion Oxidation

  3. Rusting is an electrochemical process O2 O2 Fe2O3.xH2O (rust) +O2(aq) 2OH- + Fe2+  Fe(OH)2 O2 O2 ½ O2 + 2e- +H2O  2OH- Fe2+ Fe e- e- Fe  Fe2+ + 2e-

  4. Fe2+ + 2e-Fe EΘ= -0.44V Oxidised Fe  Fe2+ + 2e- Reduced ½ O2 +2e- + H2O  2OH- ½ O2 +2e- + H2O + Fe  2OH- + Fe2+ + 2e- Precipitation Fe2+ (aq)+ 2OH- (aq)  Fe(OH)2 (s) Oxidised Fe(OH)2 (s)  Fe2O3. x H2O (s) ½ O2 +2e- + H2O 2OH-EΘ= +0.40V