87.10 Application of EMF and electrode potential 7.10.3 Determination of the reaction direction Application of Pourbaix diagram Corrosion with hydrogen evolution Corrosion with oxygen absorption > Passivation? 1.5 C Cu(oh Surface conversion? 1.0 CuO, 2 Electrochemical synthesis? 0.5 CuO 0.0 Cu 02468101214
Application of Pourbaix diagram Cu2+ Cu(OH)2 Cu pH / V 0 2 4 6 8 10 12 14 CuO2 2− Cu2O 0.0 0.5 1.0 1.5 7.10.3 Determination of the reaction direction Corrosion with hydrogen evolution Corrosion with oxygen absorption Passivation? Surface conversion? Electrochemical synthesis? §7.10 Application of EMF and electrode potential
87.10 Application of EMF and electrode potential 7.10.3 Determination of the reaction direction Divergent /Disproportionation reaction CL 2Nacl= Na Cl+ Nacio+ho HIO→1O3+12 which species can undergo divergent reaction 1.16 0.50 CIo Hs :r cIo 033Co 136 Divergent reaction occur when PR>P 0.50 0.89 元素电势图( Latimer diagram) Q=o(HOl2)=+145V 92=(O3/HO=+113V Can what species undergo divergent reaction?
Divergent /Disproportionation reaction Cl2 + 2NaCl = NaCl + NaClO + H2O Divergent reaction occur when R > L HIO → IO3 − + I2 R 2 L 3 (HIO/I ) 1.45V (IO /HIO) 1.13V − = = + = = + which species can undergo divergent reaction? 7.10.3 Determination of the reaction direction Can what species undergo divergent reaction? 元素电势图（Latimer diagram） §7.10 Application of EMF and electrode potential
87.10 Application of EMF and electrode potential 7.10.4. Advance of reaction(equilibrium constants) ∠G=0 At equilibrium ∠G=-nFE o(Fe”+/Fe2)=q(2/r) Fe3++I→>Fe2++%2I p(Fere)-p(12/)=7 T RTa o(Fe+/Fe2+)=e(Fe+/Fe2*)+In-Fe' nF RT, aF2 a, RT In K F nF (2I)=°(121,a1
7.10.4. Advance of reaction (equilibrium constants) 3 2 2 2 2 3 3 2 I Fe 2 I Fe Fe I Fe I (Fe / Fe ) (I / I ) ln ln ln ln a RT RT a a nF a nF a RT RT a a E K nF a a nF + − + + + − + + − − = − = = 3 2 3 2 3 2 Fe Fe (Fe / Fe ) (Fe / Fe ) ln RT a nF a + + + + + + = +2 I 2 2 I (I / I ) (I / I ) ln RT a nF a − − − = + 3 2 2 (Fe / Fe ) (I / I ) + + − = Fe3+ + I ¯→ Fe2+ + ½ I2 At equilibrium §7.10 Application of EMF and electrode potential G nFE = − G = 0