The original question is here
We've been given the sports drink vs orange juice challenge. To find out which has more electrolytes. I could test for conductivity but that alone wouldn't tell me which has more actual electrolytes in it. So I'm wondering if there's a way I could separate each ion from each other and measure them that way?
I'm posting it here because I'm very curious as to the answer.
Several people have suggested evaporation.
You can try evaporating the liquids and seeing what's left behind. The electrolytes will be left behind as solids.
However, the issue with evaporation is that it leaves behind all solids - electrolyte or not.
Some people have suggested conductivity measurements.
Wouldn't conductivity simply be proportional to the concentration of substances that promote conductivity?
However, this objection was raised:
Well my understanding was that different ions produce different voltages, therefore, there could be a lot of one type of electrolyte producing a large voltage but there could be more electrolytes in the other solution producing a smaller voltage. I'm not sure though as I am in first year and haven't had this completely covered yet. My professor said that conductivity might not give enough information so I may need a second approach as well, I'm not sure what he means exactly.
Is this a valid point? I guess we could empirically test out this assertion that "different ions produce different voltages" by comparing the conductivities of two otherwise identical NaCl and, say, MgBr2 solutions. Wouldn't the MgBr2 have a conductivity measurement that is roughly 1.5 times that of the NaCl solution? Or is it true that the ion's charge affects the conductivity?