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CH3041
pE LIMITS
• The limits of pE are set by the limits
of
oxidation and reduction of water which are
pH dependant.
oxidation and reduction of water which are
pH dependant.
2H2O(II-) ® O2(0) + 4e- + 4H+
» Oxidation limit: pE = 20.75 - pH
2OH2(I+) + 2e- ® H2 (0) + 2OH-
» Reduction limit: pE = -
pH
At neutral pH this gives: -7.00 < pE < 13.75
• The oxidation or reduction of water
needs
catalysts to make it kinetically fast.
catalysts to make it kinetically fast.
