Figure 7From: Tautomerism of4,4′-dihydroxy-1,1′-naphthaldazine studied byexperimental and theoretical methodsAbsorption spectra of 1 in methanol(2.7 × 10-5 M)with addition of HCl. The solid line shows the spectrum withoutacid, dashed lines correspond to the spectra with increasingconcentration of the acid added:8 × 10-6 M;1.6 × 10-5 M;2.4 × 10-5 M;3.6 × 10-5 M;6.4 × 10-5 M.Back to article page