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.

Getting Started With Solar

Getting Started With Solar

Do we really want the one thing that gives us its resources unconditionally to suffer even more than it is suffering now? Nature, is a part of our being from the earliest human days. We respect Nature and it gives us its bounty, but in the recent past greedy money hungry corporations have made us all so destructive, so wasteful.

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