APPENDIX
Acid/Base Ionization Constants at 25o C

Acid 
Formula 
Ka1 
Ka2
Ka3
Acetic acid  CH3CO2 1.8x10-5 
Acetylsalicylic acid (aspirin) HC9H7O4 3.0x10-4
Aluminum ion  Al(H2O)43+  1.2x10-5 
Arsenic acid  H3AsO4 2.5x10-4 5.6x10-8 3.0x10-13
Ascorbic acid H2C6H6O6 7.9x10-5 1.6x10-12
Benzoic acid C6H5COOH 6.3x10-5
Carbonic acid  H2CO3  4.2x10-7  4.8x10-11
Ferric ion  Fe(H2O)63+  4.0x10-3 
Formic acid  HCO2 1.8x10-4 
Hydrocyanic acid  HCN  4.0x10-10 
Hydrofluoric acid  HF  7.2x10-4 
Hydrogen peroxide  H2O2  2.4x10-12 
Hydrosulfuric acid  H2 1.0x10-7  1.0x10-19
Hypochlorous acid HClO  3.5x10-8 
Nitrous acid  HNO2  4.5x10-4 
Oxalic acid  H2C2O4  5.9x10-2  6.4x10-5
Phenol C6H5OH 1.0x10-10
Phosphoric acid H3PO4  7.5x10-3  6.2x10-8 3.6x10-13
Sulfuric acid H2SO4  very large  1.2x10-2
Sulfurous acid H2SO3 1.7x10-2 6.4x10-8
Zinc ion  Zn(H2O)42+  2.5x10-10 
Base
Formula
Kb
Ammonia  NH3  1.8x10-5 
Aniline C6H5NH2 7.4x10-10
Caffeine C8H10N4O2 4.1x10-4
Codeine C18H21O3N 8.9x10-7
Diethylamine (C2H5)2NH 6.9x10-4
Dimethylamine (CH3)2NH 5.9x10-4
Ethylamine C2H5NH2 4.3x10-4
Hydroxylamine NH2OH 9.1x10-9
Isoquinoline C9H7N 2.5x10-9
Methylamine CH3NH2 4.2x10-4
Morphine C17H19O3N 7.4x10-7
Piperidine C5H11N 1.3x10-3
Pyridine C5H5N 1.5x10-9
Quinoline C9H7N 6.3x10-10
Triethanolamine C6H15O3N 5.8x10-7
Triethylamine (C2H5)3N 5.2x10-4
Trimethylamine (CH3)3N 6.3x10-5
Urea N2H4CO 1.5x10-14