Structure and Properties of Carboxylic Acids TABLE15.2 Acidity of Some Carboxylic Acids Structure Ka pKa CF3CO2H 0.59 0.23 Stronger acid HCO2H 1.77×10-4 3.75 HOCH2CO2H 1.5×10-4 3.83 CsHsCO2H 6.46×10-5 4.19 H2C-CHCO2H 5.6×10-5 4.25 CH3CO2H 1.75×10-5 4.76 CH3CH2CO2H 1.34×10-5 4.87 Weaker CH3CH2OH(ethanol) (1.00×10-16) (16.00) acid Structure and Properties of Carboxylic Acids