What is the net ionic equation for the reaction of solid iron with aqueous copper sulfate? (Hint: First use the activity series to write the formula unit equation!) 1. 2 Fe(s) + 3 CuSO4(aq) → Fe2(SO4)3(s) + 3 Cu(s) 2. 2 Fe(s) + 3 Cu2+(aq) + 3 SO2− 4 (aq) → Fe2(SO4)3(s) + 3 Cu(s) 3. No reaction occurs. 4. 2 Fe(s) + 3 CuSO4(aq) → Fe2(SO4)3(aq) + 3 Cu(s) 5. 2 Fe(s) + 3 Cu2+(aq) + 3 SO2− 4 (aq) → 2 Fe3+(aq) + 3 SO2− 4 (aq) + 3 Cu(s) 6. 2 Fe(s) + 3 Cu2+(aq) → 2 Fe3+(aq) + 3 Cu(s)