Specifically: Suppose I add equal parts (i.e. the same number of moles of each) sodium bicarbonate and potassium sulfate into a container of distilled water large enough to dissolve them completely. In a second container of water, I add potassium bicarbonate and sodium sulfate. Are these two containers now physically identical? (That is, is there any experiment that could tell them apart?) My understanding is that each now contains free-floating Na+, K+, S-, and HCO3- ions. And if I evaporate away all the water, what will be left behind in each container?
If I replace the potassium and/or sodium with, say, magnesium or calcium, and the bicarbonate and/or sulfate with chloride or citrate, do the same principles hold? (Assuming the resulting salts are water-soluble - some, like calcium carbonate, won't be.)
(I'm not sure if the list of cations and anions above have much in common chemically. My interest relates to the fact that they can be added to water to simulate the chemical makeup and flavor of natural mineral spring water.)
(PS: What's a more elegant way to say "the same number of moles of each?" If I say to mix things in equal parts, or in some ratio, I would normally specify whether I mean by mass, by volume or... how do I say "by number of moles?")