 Carboxylic acids are typically weak acids, meaning that they only partially dissociate into H3O+ cations and RCOO− anions in neutral aqueous solution.For example, at room temperature, in a 1-molar solution of acetic acid, only 0.4% of the acid are dissociated.Electron-withdrawing substituents, such as -CF3 group, give stronger acids (the pKa of formic acid is 3.75 whereas trifluoroacetic acid, with a trifluoromethyl substituent, has a pKa of 0.23).