70 likes | 309 Views
Podcast 18.2. Acids and Base Strength. What makes an acid/base strong?. Strong acids/bases to know. Acids HCl H 2 SO 4 HNO 3 HClO 4 HClO 3 HBr HI. Bases NaOH KOH RbOH CsOH Ca(OH) 2 Ba(OH) 2. K a and K b. K a is the acid dissociation constant
E N D
Podcast 18.2 Acids and Base Strength
Strong acids/bases to know Acids • HCl • H2SO4 • HNO3 • HClO4 • HClO3 • HBr • HI Bases • NaOH • KOH • RbOH • CsOH • Ca(OH)2 • Ba(OH)2
Ka and Kb Ka is the acid dissociation constant Kb is the base dissociation constant For weak acid: HA + H2O H3O+ + A- Ka = [H3O+][A-] [HA] For weak base: BOH + H2O HB+ + OH- Kb = [HB+][OH-] [BOH]
Solve Ka problems the same way you would solve equilibrium problems. Example: A 3.0 M solution of a certain monoprotic acid has a [H3O+]eq = 2.5 x 10-4 What is the Ka for the acid?
Polyprotic Acids have a Ka value for each proton H3PO4 H2PO4- + H+ HPO42- + H+ PO43- + H+
Practice Problem Ammonia is a weak B-L base. When a 0.75 M ammonia solution reaches equilibrium, the [OH-] = 4.33 x 10-3 M. What is the Kb for ammonia?