How clearcut is the distinction between strong ions, weak ions & non-electrolytes?
The distinction is not completely clearcut of course BUT for practical purposes it is a sufficiently accurate & useful approximation. Stewart uses the value of the dissociation constant (KA) to provide a clear (but still a bit arbitrary) distinction between the three groups: • Non-electrolyte : KA <>-12 Eq/l • Weak electrolyte : KA between 10-4 and 10-12 Eq/l • Strong electrolyte : KA > 10-4 Eq/l – – – – – – – – – – – – – – – – – – – – – – – – – – – – – Extra Notes: • Strong in this section means strongly dissociated and does not mean a ‘strong solution’ (ie meaning a concentrated one). • Those strong ions eg Ca++ which are partly bound to plasma proteins don’t quite fit into the system but this is not a major problem partly because their concentrations are low.
