Final answer:
Option a) Ca(C2H3O2)2 + Na2SO4 will form a precipitate since calcium sulfate (CaSO4) is insoluble in water. The other pairs of solutions listed contain ions that usually form soluble compounds in water, and therefore do not produce a precipitate.
Step-by-step explanation:
To determine which pairs of aqueous solutions will form a precipitate when mixed, we can apply solubility rules. A precipitation reaction occurs when two ionic compounds in solution are combined and form an insoluble product, known as the precipitate. By considering the reactions:
- a) Ca(C2H3O2)2 + Na2SO4
- b) KOH + Na2S
- c) KNO3 + LiOH
- d) (NH4)2SO4 + KI
- e) None of the above solution pairs will produce a precipitate.
If we look at each option and apply the solubility rules, we find that option a) is the correct answer since calcium sulfate (CaSO4) is insoluble in water, leading to the formation of a precipitate.
The other pairs do not form precipitates under standard conditions, as potassium, sodium, ammonium, nitrate, and acetate ions generally form soluble compounds in water.