A would be the answer to this question
I believe the correct answer is A
The answer is atomic weight !
<u>Answer:</u> The other product formed is potassium chloride.
<u>Explanation:</u>
Precipitation reaction is defined as the chemical reaction in which an insoluble salt is formed when two solutions are mixed containing soluble substances. The insoluble salt settles down at the bottom of the reaction mixture.
The chemical equation for the reaction of potassium phosphate and magnesium chloride follows:

By Stoichiometry of the reaction:
2 moles of aqueous solution of potassium phosphate reacts with 3 moles of aqueous solution of magnesium chloride to produce 1 mole of solid magnesium phosphate and 6 moles of aqueous solution of potassium chloride.
Hence, the other product formed is potassium chloride.
it will expand as water moves into it.