Acids and bases are compounds that, when added to an aqueous solution, change the amounts of H3O+ and OH- ions in solution. Acids increase the amount of H3O+ in solution by donating protons (H+) to water (H2O), forming H3O+. Bases increase the amount of OH- by removing protons from water, forming OH-. Acidic solutions have more H3O+ than OH- in them, while the opposite is the case for basic solutions. …showed first 75 words of 511 total…

…showed last 75 words of 511 total…and blue in alkaline solutions. There are three theories that identify a singular characteristic which defines an acid and a base: the Arrhenius theory, for which the Swedish chemist Svante Arrhenius was awarded the 1903 Nobel Prize in chemistry; the Brönsted-Lowry, or proton donor, theory, advanced in 1923; and the Lewis, or electron-pair, theory, which was also presented in 1923. Each of the three theories has its own advantages and disadvantages; each is useful under certain conditions.