A salt may be prepared by the reaction of one salt with another salt, particularly if one of the products is insoluble.

In which one of the following reactions is this demonstrated?
(NH4)2CO3 + K2SO4 \->(NH4)2SO4 + K2CO3
CuCl2 + 2 NH4NO3 \-> Cu(NO3)2 + 2 NH4Cl
Sr(NO3)2 + 2 KCl \-> SrCl2 + 2 KNO3
BaCl2 + Na2S \-> BaS + 2 NaCl
NaNO3 + KCl \-> NaCl + KNO3

Please disregard this question. It's been answered: BaCl2 + Na2S \-> BaS + 2 NaCl

The reaction that demonstrates the preparation of a salt by the reaction of one salt with another salt, particularly if one of the products is insoluble is:

BaCl2 + Na2S -> BaS + 2 NaCl.

Let's break down the reaction and explain how it fits the given criteria:

Barium chloride (BaCl2) and sodium sulfide (Na2S) are both salts. When they react together, they exchange ions to form new products. In this case, one of the products, barium sulfide (BaS), is insoluble and will precipitate out of the solution.

BaCl2 (aq) + Na2S (aq) -> BaS (s) + 2 NaCl (aq)

Here's how you can identify the reaction that demonstrates the given criteria:

1. Look for two salt compounds on each side of the reaction arrow.
2. Check if one of the products of the reaction is insoluble (in the solid state) while the other product remains in the solution.
3. In the correct reaction, both reactant salts should exchange ions to form new products.

By applying these criteria to the given options, we can see that only the reaction:

BaCl2 + Na2S -> BaS + 2 NaCl

demonstrates the preparation of a salt by the reaction of one salt with another salt, with one of the products being insoluble.