So for example, let's look at HCL. HCL dissociates in water into an H plus ion and a chloride ion. And that means because HCL increases the concentration of our H plus ions found in water, by definition, HCL must be an Iranian acid. Now, Iranian bases are those substances that increase oh concentration in water. So for example, let's look at sodium Hydroxide. Sodium Hydroxide, when mixed with water, dissociates into sodium in an oh ion.