Final answer:
When mixing Ba(NO₃)₂ with K₂SO₄, barium sulfate (BaSO₄) is the precipitate formed. BaSO₄ is insoluble in aqueous solution, unlike the other product, KNO₃, which remains dissolved.
Step-by-step explanation:
When a solution of barium nitrate, Ba(NO₃)₂, is mixed with a solution of potassium sulfate, K₂SO₄, the resulting double-replacement reaction will form a precipitate. The insoluble product of this reaction will be barium sulfate, BaSO₄, based on solubility rules. The other product, potassium nitrate KNO₃, remains soluble in the aqueous solution.
The chemical equation for the reaction is:
Ba(NO₃)₂ (aq) + K₂SO₄ (aq) → BaSO₄ (s) + 2 KNO₃ (aq)
This demonstrates that option d.) BaSO₄ is the correct choice for the precipitate formed in the reaction.