Dissociation Constants for Common Acids and Bases

Dissociation Constants for Common Acids and Bases

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

acid	formula	pK_a1	pK_a2	pK_a3

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	pK_b1	pK_b2

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

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