- Dissociationof the solute. For NaCl,msshould be replaced by
mNaþmCl, assuming complete dissociation. The broken line in Figure 8.1
has been drawn on this assumption. It is seen that dissociation explains by
far the greater part of the nonideality for NaCl, but not all of it. - Solute molecule sizeor, more precisely, the parameterqin Eq.
(8.4). Figure 8.1 shows a few points calculated forb¼1, which implies no
FIGURE8.1 Water activityðawÞversus mole fraction of water (xw) for aqueous
solutions of sucrose, NaCl, and Na-caseinate. Also given are the ideal relationðaw¼
xwÞ, the relation for NaCl assuming complete dissociation (broken line), and some
points () for sucrose according to Eq. (8.4).