%0 Journal Article
%T A triazole derivative as a new acid-base indicator
%A Volkan Numan Bulut
%A Celal Duran
%A Ali Gundogdu
%A Mustafa Soylak
%A Nuri Yildirim
%A Mehmet Tufekci
%J Bulletin of the Chemical Society of Ethiopia
%D 2010
%I Chemical Society of Ethiopia
%X In this study a new pH indicator, 3-benzyl-4-p-nitrobenzylidenamino-4,5-dihydro-1,2,4-triazole-5-on (BPNBAT), soluble in acetonitrile:water (1:4), was developed. The estimation of pH is possible either from the position of the absorption maxima or from the absorbance intensity at a constant wavelength. This feature allowed us to determine the basic transition range of the medium because BPNBAT is colorless at pH lower than 8.5 and showed strong yellow-green color with high extinction coefficient in the pH range of 8.5¨C10.1. pKa, pH at equivalent point and the molar absorptivity (in the aqueous medium at 380 nm) of BPNBAT are determined as 9.3, 8.3 and 8.8 x 103 L.mol-1.cm-1,respectively. The color change at the transition range can be attributed to the resonance structures of BPNBAT. The triazole compound was compared with thymolphthalein for accuracy test.   KEY WORDS: Acid-base indicator, 3-Benzyl-4-p-nitrobenzylidenamino-4,5-dihydro-1,2,4-triazole-5-on, UV-Vis spectrometry, Resonance, Transition point, Titrimetry    Bull. Chem. Soc. Ethiop. 2010, 24(3), 457-460.
%U http://www.ajol.info/index.php/bcse/article/view/60694