A precipitation reaction occurs when equal volumes of 0.2M Pb(NO₃)₂ and 0.2M KI are mixed. The net ionic equation for this reaction is ________.
1) Pb²⁺(aq) + 2I-(aq) → PbI₂(s)
2) PbI₂(s) → Pb²⁺(aq) + 2I-(aq)
3) Pb(NO₃)₂(aq) + 2KI(aq) → PbI₂(s) + 2KNO₃(aq)
4) Pb(NO₃)₂(aq) + KI(aq) → PbI₂(s) + KNO₃(aq)
