Final answer:
In the reaction BaCl2(aq) + Na2SO4(aq) → BaSO4(s) + 2NaCl(aq), the spectator ions are sodium (Na+) and chloride (Cl−) ions, as they do not participate in the formation of the insoluble precipitate, barium sulfate (BaSO4).
Step-by-step explanation:
The student is asking about the spectator ions in the reaction between barium chloride (BaCl2) and sodium sulfate (Na2SO4) to form barium sulfate (BaSO4) and sodium chloride (NaCl). Spectator ions are ions that do not participate in the actual chemical reaction and remain unchanged in solution before and after the reaction. In the provided reaction, the spectator ions are Na+ (sodium ions) and Cl− (chloride ions).
The complete ionic equation shows all of the soluble ionic species as separate ions: Ba2+ (aq) + 2 Cl− (aq) + 2 Na+ (aq) + SO42− (aq) → BaSO4(s) + 2 Na+ (aq) + 2 Cl− (aq).
To find the net ionic equation, we identify and remove the spectator ions from the equation. This leaves us with the net ionic equation: Ba2+ (aq) + SO42− (aq) → BaSO4 (s), which shows the formation of the insoluble precipitate, BaSO4.