The Kelvin equation, (17-16), predicts that solubility increases to infinity as the crystal diameter decreases to zero. However, measurements by L. Harbury [J. Phys. Chem., 50, 190-199 (1946)] for several inorganic salts in water show a maximum in the solubility curve and a solubility that approaches zero as crystal size is reduced to zero. Harbury's explanation is that the surface energy of the crystals depends not only on interfacial tension, but also on surface electrical charge, given by

where

q = electrical charge on the crystal

K = dielectric constant

Modify (17-16) to take into account electrical charge. Make sure your equation predicts amaximum.

Transcribed Image Text:

2q v;/TKRT D