Which equation represents a neutralization reaction?
1) Pb(NO₃)₂ + 2ki → PbI₂ + 2KNO₃
2) Fe₂O₃ + HCl → feCl₃ + H₂O
3) AgNO₃ + HCl → AgCl + HNO₃
4) NaOH(aq) + HCl(aq) → NaCl(aq) + H₂O (l)