Potentiometric and spectrophotometric methods were applied to the determination of the apparent ionization constants, in 70% ethanol, of 120 polycyclic aromatic compounds. These were phenols, carboxylic acids, and chiefly amines derived from naphthalene, biphenyl, phenanthrene, chrysene, pyrene, dibenzofuran, dibenzothiophene, carbazole, diphenyl sulfide, diphenylmethane, and especially from fluorene. The effect of the ...