There are many types of acid or bases. Based on the Arrhenius definition,
* An Arrhenius acid donates H⁺ in a solution (like HCl, HNO₃, H₂SO₄)* An Arrhenius base yield OH⁻ in a solution (like NaOH, KOH, Mg(OH)₂)
Other types of acids and bases are the Lewis acids/bases and the Bronsted-Lowry acids/bases.