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Acid & Base Definitions. Arrhenius Theory Acid -substance that contains hydrogen and produces H + in aqeous solution (soln.) any protonic acid is an Arrhenius acid: H 2 SO 4 , HCl, HNO 3 ....
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Acid & Base Definitions • Arrhenius Theory • Acid-substance that contains hydrogen and produces H+ in aqeous solution (soln.) • any protonic acid is an Arrhenius acid: H2SO4, HCl, HNO3 .... • Base-substance that contains the hydroxyl (OH) group and produces hydroxide ions (OH-) in aqeous soln. • Metal hydroxides (hydroxyl bases) are Arrhenius bases • Neutralization: H+(aq) + OH-(aq) H2O(l) • HA(aq)+ OH-(aq) H2O(l) + A-(aq)
Brønsted-Lowry Theory • Acids-Proton donor • Any hydrogen containing compound capable of releasing a proton: All acids that we have discussed so far. • Bases-Proton acceptor • Metal hydroxides, ammonia, ammonia derivatives and more. • Acid-Base Rxns: HA(aq) + B(aq) A-(aq) + BH+(aq) • acid base • HNO3 + H2O - + H3O+ • proton transfer • H2O + NH3 OH- + NH4+
Lewis Theory • Acids - lone pair acceptor • any electron deficient compound: BF3 • Bases - lone pair donor • any compound with a lone pair for donation: NH3, CO, O2 , ... • Acid-Base rxn involves the formation of a coordinate covalent bond • Coordinate Covalent Bond
Autoionization • H2O + H2O H3O+ + OH- • acid base • What kind of acid is shown in the above reaction? Base? • Arrhenius, Brønsted-Lowry & Lewis Acid • Arrhenius, Brønsted-Lowry & Lewis Base
Amphoterism • Amphoterism - the ability of a substance to act as an acid or a base. • A substance that exhibits amphoterism is said to be amphoteric • Water is amphoteric because it can act as an acid or a base. • Specifically, water is amphiprotic because it can either be a proton donar or acceptor (Brønsted-Lowery definition or an acid & base) • Many insoluble metal hydroxides are amphoteric: • Cu(OH)2(s) + 2H+(aq) Cu2+(aq)+ 2 H2O • base acid • Cu(OH)2(s)+2OH-(aq) Cu(OH)42-(aq) • acid base