Acidity constants of benzidine in aqueous solutions.
The acidity constants of benzidine (Bz) in aqueous solutions determined potentiometrically at 25 degrees were K(a1) = (1.11 +/- 0.08) x 10(-5), K(a2) = (1.45 +/- 0.12) x 10(-4). The apparent mixed constants in 0.1M sodium nitrate are K(a1) = (5.37 +/- 0.28) x 10(-6) and K(a2) = (1.14 +/- 0.09) x 10(-4). The ultraviolet spectra were recorded as a function of pH and analysed with these constants to obtain the absorption spectra of H(2)Bz(2+), HBz(+) and Bz; the corresponding wavelengths of maximal absorption are 247, 273 and 278 nm, and molar absorptivities 1.63 x 10(4), 1.76 x 10(4) and 2.26 x 10(4) 1.mole(-1).cm(-1).
Reartes
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Comisión Nacional de Energía Atómica, Avenida del Libertador 8250, Buenos Aires 1429, Argentina.
Liberman
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Blesa
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