Bronsted-Lowry acids are “proton donors.” Hydrogen chloride (HCl) is an example of Bronsted-Lowry acids. When hydrogen chloride is added to water, the attraction between the positively-charged hydrogen ion in the hydrogen chloride and the negatively-charged oxygen in the water is strong enough that the hydrogen ion is removed. Hydrogen chloride is therefore called a “proton donor.”
In turn, Bronsted-Lowry bases are “proton acceptors.” They react with Bronsted-Lowry acids as the negatively-charged force that pulls protons from the acid. An example of a Bronsted-Lowry base is ammonium (NH3), which can gain a proton to form ammonia (NH4).