A.↪ The gross ionic equation for the reaction between barium chloride (BaCl2) and magnesium sulfate (MgSO4) can be written as:
▶ Ba^2+ + 2Cl^- + Mg^2+ + SO4^2- → BaSO4 (s) + MgCl2
B. ↪The spectator ions are the ions that do not participate directly in the chemical reaction and remain unchanged before and after the reaction. In this case, the spectator ions are Cl^- and Mg^2+.
C. ↪To write the net ionic equation, we remove the spectator ions from the gross ionic equation:
Net ionic equation: Ba^2+ + SO4^2- → BaSO4 (s)
D. ↪The reductant is the species that gets oxidized (loses electrons), and the oxidant is the species that gets reduced (gains electrons). In this reaction:
Barium (Ba) loses two electrons to become Ba^2+ (oxidized), so it is the reductant. Sulfate (SO4) gains the two electrons from barium to become SO4^2- (reduced), so it is the oxidant.