Ionization Constants of Weak Acids

Acid Formula <emKa at 25 °C Lewis Structure
acetic CH3CO2H [latex]1.8\times{10}^{-5}[/latex]
arsenic H3AsO4 [latex]5.5\times{10}^{-3}[/latex]
H2AsO4− [latex]1.7\times{10}^{-7}[/latex]
HAsO42− [latex]5.1\times{10}^{-12}[/latex]
arsenous H3AsO3 [latex]5.1\times{10}^{-10}[/latex]
boric H3BO3 [latex]5.4\times{10}^{-10}[/latex]
carbonic H2CO3 [latex]4.3\times{10}^{-7}[/latex]
HCO3− [latex]5.6\times{10}^{-11}[/latex]
cyanic HCNO [latex]2\times{10}^{-4}[/latex]
formic HCO2H [latex]1.8\times{10}^{-4}[/latex]
hydrazoic HN3 [latex]2.5\times{10}^{-5}[/latex]
hydrocyanic HCN [latex]4.9\times{10}^{-10}[/latex]
hydrofluoric HF [latex]3.5\times{10}^{-4}[/latex]
hydrogen peroxide H2O2 [latex]2.4\times{10}^{-12}[/latex]
hydrogen selenide H2Se [latex]1.29\times{10}^{-4}[/latex]
HSe– [latex]1\times{10}^{-12}[/latex]
hydrogen sulfate ion HSO4− [latex]1.2\times{10}^{-2}[/latex]
hydrogen sulfide H2S [latex]8.9\times{10}^{-8}[/latex]
HS– [latex]1.0\times{10}^{-19}[/latex]
hydrogen telluride H2Te [latex]2.3\times{10}^{-3}[/latex]
HTe– [latex]1.6\times{10}^{-11}[/latex]
hypobromous HBrO [latex]2.8\times{10}^{-9}[/latex]
hypochlorous HClO [latex]2.9\times{10}^{-8}[/latex]
nitrous HNO2 [latex]4.6\times{10}^{-4}[/latex]
oxyalic H2C2O4 [latex]6.0\times{10}^{-2}[/latex]
HC2O4− [latex]6.1\times{10}^{-5}[/latex]
phosphoric H3PO4 [latex]7.5\times{10}^{-3}[/latex]
H2PO4− [latex]6.2\times{10}^{-8}[/latex]
HPO42− [latex]4.2\times{10}^{-13}[/latex]
phosphorous H3PO3 [latex]5\times{10}^{-2}[/latex]
H2PO3− [latex]2.0\times{10}^{-7}[/latex]
sulfurous H2SO3 [latex]1.6\times{10}^{-2}[/latex]
HSO3− [latex]6.4\times{10}^{-8}[/latex]