Question

As far as I can tell the answer for all of them is dissolution but wanted to ask anyway just in case I was wrong and get a proper answer along with explanation.
With reference to Table 4.2, suggest one method by which you might separate (a) K+ from Ag+, (b) Ba2+ from Pb2+, (c) NH4+ from Ca2+, and (d) Ba2+ from Cu2+. All cations are assumed to be in aqueous solution, and the common anion is the nitrate ion.

Answer 1

Chart Attached here.

Answer 2

i think they want specific examples, for a) you could add a sulfate and selectively precipitate the Ag+ ion

Answer 3

sulfate?

Answer 4

yeah

Answer 5

@aarong example please

Answer 6

of a sulfate? it can be any that isn't insoluble, like \(Li_2SO_4\)

Answer 7

@aaronq but isn't Li already soluble and Ag insoluble?! Wouldn't the separate anyway especially since they both have a positive charge.

Answer 8

sorry for the late reply, i'm not getting notifications.

Li is soluble, yes, that's what we want.

when you put Li2SO4 in water it will separate, the \(SO_4^{2-}\) ions will "capture" the Ag+ ions from solution and cause them to precipitate (by forming \(Ag_2SO_4\)).

hence you will separate the Ag+ ions from the K^+ ions

Answer 9

The K+ ions remain in solution and you can filter out the Ag2SO4 precitpiate

Answer 10

@aaronq but wouldn't Ag already be separated from the solution especially since it is a solid form that is insoluble anyway and plus the atoms are positively charged they would repel each other.

Answer 11

Ag is not always a solid. When they write Ag+ it means that it's aqueous (i.e. in solution, not solid). And that's not what mean by separated.