Dissociation Constants for Common Acids and Bases

p-functions for common acids and bases
(at 25oC)


acid formula pKa1 pKa2 pKa3
acetic HC2H3O2 4.74
acetylsalicylic C8H7O2COOH 3.48
acrylic HC3H3O2 4.26
aluminum ion Al3+ 5.01
arsenic H3AsO4 2.30 7.03 11.53
arsenous HAsO2 9.18
ascorbic H2C6H6O6 4.10 11.80
benzoic C6H5COOH 4.20
boric H3BO3 9.23
bromoacetic HC2H2BrO2 2.90
butyric HC4H7O2 4.83
carbonic H2CO3 6.37 10.25
chloroacetic CH2ClCOOH 2.85
chlorous HclO2 1.92
chromium ion Cr3+ 4.0
cinnamic HC9H7O2 4.44
citric H3C6H5O7 3.13 4.76 6.40
cyanic HCNO 3.46
cyanuric HC3H2N3O3 6.78
dichloroacetic HC2HCl2O2 1.26
fluoroacetic HC2H2FO2 2.59
formic HCOOH 3.75
germanic H2GeO3 9.0 12.4
hydrazoic HN3 4.72
hydrocyanic HCN 9.23
hydrofluoric HF 3.16
hydrogen peroxide H2O2 11.65
hydroselenic H2Se 3.89 11.0
hydrosulfuric H2S 6.88 14.15
hydrotelluric H2Te 2.64 10.80
hypobromous HBrO 9.24
hypochlorous HClO 7.55
hypoiodous HIO 10.64
hyponitrous H2N2O2 7.05 11.4
hypophosphorous H3PO2 1.23
iodic HIO3 0.80
iodoacetic HC2H2IO2 3.18
iron(II)ion Fe2+ 6.74
iron(III)ion Fe3+ 2.83
lactic HC3H5O3 3.08
maleic HOOCCH:CHCOOH 1.84 6.07
malonic H2C3H2O4 2.82 5.70
nitrous HNO2 3.14
oxalic H2C2O4 1.23 4.19
phenol HOC6H5 10.00
phosphoric H3PO4 2.12 7.21 12.67
phosphorous H3PO3 1.80 6.15
phthalic H2C8H4O4 2.92 5.41
propionic HC3H5O2 4.87
salicylic HC7H5O3 1.96
selenic H2SeO4-3 1.66
selenous H2SeO3 2.64 8.27
succinic H2C4H4O4 4.21 5.64
sulfuric H2SO4 none 1.92
sulfurous H2SO3 1.89 7.21
thiophenol HSC6H5 6.49
trichloroacetic HC2Cl3O2 0.52
zinc ion Zn2+ 8.96
base formula pKb1 pKb2
ammonia NH3 4.76
aniline C6H5NH2 9.37
codeine C18H21O3N 6.05
diethylamine (C2H5)2NH 4.51
dimethylamine (CH3)2NH 3.23
ethylamine C2H5NH2 3.36
hydrazine N2H4 5.77 15.05
hydroxylamine HONH2 9.04
methylamine CH3NH2 3.38
morphine C17H19O3N 6.13
piperidine C5H11N 2.88
pyridine C5H5N 8.70
quinoline C9H7N 9.20
triethanolamine C6H15O3N 6.24
triethylamine (C2H5)3N 3.28
trimethylamine (CH3)3N 4.20