AMINES60522.4The electron-donating amino group and the electron-withdrawing nitro group are directly conjugatedinp-nitroaniline. The planar geometry ofp-nitroaniline suggests that the delocalized resonance formshown is a major contributor to the structure of the compound.22.5The pKbof an amine is related to the equilibrium constant KbbypKb52log KbThe pKbof quinine is thereforepKblog (131026)56the values of Kband pKbfor an amine and Kaand pKaof its conjugate acid are given byKa3Kb51310214 andpKa1pKb514The values of Ka and pKafor the conjugate acid of quinine are thereforeKa555131028andpKa5142pKb514265822.6The Henderson–Hasselbalch equation described in Section 19.4 can be applied to bases such asamines, as well as carboxylic acids. The ratio [CH3NH31]y[CH3NH2] is given by 5The ionization constant of methylammonium ion is given in the text as 2310211. At pH57 thehydrogen ion concentration is 1
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This note was uploaded on 10/03/2011 for the course CHM 2210 taught by Professor Reynolds during the Fall '01 term at University of Florida.