Identify the reactants and products in the given chemical equation: NH4Cl(aq) + NaOH(aq) → H2O(l) + NH3(g) + NaCl(aq).
Write the dissociation of each aqueous compound into its ions: NH4Cl(aq) dissociates into NH4^+(aq) and Cl^-(aq), NaOH(aq) dissociates into Na^+(aq) and OH^-(aq), and NaCl(aq) dissociates into Na^+(aq) and Cl^-(aq).
Combine the dissociated ions to form the complete ionic equation: NH4^+(aq) + Cl^-(aq) + Na^+(aq) + OH^-(aq) → H2O(l) + NH3(g) + Na^+(aq) + Cl^-(aq).
Identify and cancel out the spectator ions, which are ions that appear on both sides of the equation without undergoing any change. In this case, Na^+(aq) and Cl^-(aq) are spectator ions.
Write the net ionic equation by removing the spectator ions: NH4^+(aq) + OH^-(aq) → H2O(l) + NH3(g).