There are three acid-base theories: Arrhenius, Bronsted-Lowry, and Lewis. Among the three, only the Bronsted-Lowry theory defines acids and bases based on the transfer of protons H⁺.
Mg(OH)₂ (s) + H₂SO₄ → MgSO₄ (s) + 2 H₂O (l)
Fe(NO₃)₃ (aq) + 3 KOH (aq) → Fe(OH)₃ (s) + 3 KNO₃ (aq)
Zn (s) + Cu(NO₃)₂ (aq) → Zn(NO₃)₂ (aq) + Cu(s)
Mg (s) + Cu(NO₃)₂ (aq) → Mg(NO₃)₂ + Cu (s)
HCl (aq) + KOH (aq) → KCl (aq) + H₂O (l)
NH₃ (aq) + HCl (aq) → NH₄Cl (aq)
[tex]\text{HCl} \to \text{H}^{+}\;(aq) + \text{Cl}^{-}\;(aq)\\\begin{array}{ll}\text{Ionic equation} & \text{NH}_3 \;(aq)+ \text{H}^{+}\;(aq) +\text{Cl}^{-}\;(aq)\to {\text{NH}_4}^{+} \;(aq)+\text{Cl}^{-}\;(aq)\\\text{Net Ionic equation} & \text{NH}_3 \;(aq)+ \text{H}^{+}\;(aq) \to {\text{NH}_4}^{+} \;(aq)\end{array}[/tex]