pka_value	data_source	charge_state_pre	charge_state_post	microspecies_pre	microspecies_post	molid	smiles
4.2	IUPAC digitized pKa	0	-1	CC#C/C=C/C(=O)O	CC#C/C=C/C(=O)[O-]	mol9536	CC#C/C=C/C(=O)O
4.19999980926514	QSARToolbox	0	-1	CC#C/C=C/C(=O)O	CC#C/C=C/C(=O)[O-]	mol9536	CC#C/C=C/C(=O)O