Acid Base Reactions & Theories Chapter 20 part III
Acid Base Reactions • Acid Anhydrides & water form Acid • SO3 + H2O H2SO4 • Acids & Metals form Salt and Hydrogen Gas • 2HCl + Mg H2 (g) + MgCl2 • Acid & Base Form Salt & Water • HNO3 + KOH H2O + KNO3 • Acid and Carbonates form Carbon dioxide, salt & water • 2HCl + MgCO3 H2O + MgCl2 + CO2
Arrhenius Theory • Arrhenius proposed (1883) that ionic compounds dissociate and can become free ions acting as separate entities in solution.
Arrhenius Theory • ACID: Produces H+1 in WaterBASE: Produces OH-1 in Water • HCl(aq) H+1 + Cl-1HNO3(aq) H+1 + NO3-1NaOH(aq) Na+1 + OH-1NH3(aq) NH4+1 + OH-1
Bronsted & Lowry proposed a new acid-base theory in 1923. • ACID: PROTON DONORBASE: PROTON ACCEPTOR
Also: • Since protons are always transferred in the Arrenhius theory, all Arrhenius acid/base reactions are also Bronsted-Lowry acid/base reactions. Bronsted-Lowry theory expands Arrenhius theory to include any proton transfer (water not required).
Lewis Theory • In 1938 Gilbert Lewis proposed a more general acid base theory.
Lewis Acids • ACID:Accepts pair of electrons for sharingBASE:Donates pair of electrons for sharing