Page:Text-book of Electrochemistry.djvu/178

the formula ${\displaystyle K\times C_{\mathrm {A} \mathrm {B} }=C_{\mathrm {A} }\times C\mathrm {B} ={\binom {a}{v}}^{2}}$ can be transformed into—

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The relationship expressed in this formula is known as Ostwald's law, or the law of dilution (8).

The constant K is termed the electrolytic dissociation constant of acetic acid.

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log K = 5-25 - 10(5-25). K = 00000178.

As is evident from the numbers given, the calculated and observed degrees of dissociation agree extremely well. In no other field in which the law of mass action has been applied have so good results been, obtained.

This agreement between theory and practice, however, is only found for weak electrolytes, of which Ostwald investigated the acids and Bredig the bases (9),

It is just possible that even in this case the law of mass action is not undisturbed by other factors. The deviation from the law seems to be greater the stronger the acid is. Amongst the stronger organic acids deviations occur, e,g, with formic acid, and to an even greater extent with the