These two potentials are equated to reflect the condition of equilibrium of reaction (10.33). The oxygen pressure in the two equations cancel and the resulting product of the H+ and OH-concentrations is the water dissociation constant:
This result could also have been obtained by direct application of Eq (10.32).
In neutral water (i.e., neither acidic nor basic), cH+ = cOH_ = -JKW = 10-7 M . A more convenient description of acidity is the pH:
So that the pH of pure water at 25oC is 7.
The standard electrode potentials are temperature dependent. The coolant in nuclear reactors is high pressure water at 300oC, at which temperature the dissociation constant is 10-11 and neutral water has a pH of 5.5.
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Global warming is a huge problem which will significantly affect every country in the world. Many people all over the world are trying to do whatever they can to help combat the effects of global warming. One of the ways that people can fight global warming is to reduce their dependence on non-renewable energy sources like oil and petroleum based products.