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Brønsted -Lowry Acids & Bases. By Lev Corne And Naomi Willow. Basic History. In 1913 two chemists, J. N. Brønstead , and T. M. Lowry expanded on the Arrheinus acid deffention . During their expasion they discovered:
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Brønsted-Lowry Acids & Bases By Lev Corne And Naomi Willow
Basic History • In 1913 two chemists, J. N. Brønstead, and T. M. Lowry expanded on the Arrheinus acid deffention. • During their expasion they discovered: -Because H+ is a proton, all acids that are defined by Arrhenius give protons to water and are Brønsted-Lowry acids. Example: Hydrogen chloride acts as a Brønsted-Lowry acid when reacted with ammonia. The HCl transfers protons to NH3 HCl + NH3 → NH4+ + Cl-
Vocabulary • Brønsted-Lowry acid: A molecule or ion that is a proton donor • Brønsted-Lowry base: A molecule or ion that is a proton acceptor • Brønsted-Lowry acid-base reaction: When protons are transferred form one (the acid) to another (the base). • Monoproticaicd: An acid that can only donate one proton (hydrogen ion) per molecule. • Polytropic Acid: An acid that can donate more than one proton per molecule.
Monoprotic Acids Monotropic Examples: Perchloricacid, hydrochloric acid, and nitric acid. • Example of an eqn. that shows a monotropic acid, HCl donating a proton to a water molecule. The HCl ionizes from the H3O+ and Cl- ions. The Cl- has no Hs to lose so HCl has one ionization step. HCl(g) + H2O(l) →H3O+ (aq) + Cl
PolyproticAcids • PolyproticExamples: Sulfuric acid, phosphoric acid. • The ionization of a polyprotichappens in stages. The acid loses its hydrogen atoms one at a time. Sulfuric acid ionizes in 2 stages. In its first ionization sulfuric acid is strong, It is completely converted to hydrogen sulfate ions. H2SO4(l) + H2O→ H3O+(aq) + HSO4(aq) The hydrogen sulfate ion is a weak acid. It establishes the following equilibrium solution: HSO4(aq) + H2O → H3O+(aq) + SO42-(aq)