This functional group appears as a side product of the Lossen rearrangement used to produce iso·cyanate. The Hammett equation describes substitutions of a benzene derivative containing this functional group. Diazo·methane is used to homologate these functional groups in the Arndt-Eistert reaction. PBr3 catalyzes the halogenation of these functional groups in the Hell-Volhard-Zelinsky reaction. (15[1])Hydrolysis of (*) nitriles produce these functional groups, which are reacted with thionyl chloride to make acyl chlorides. Two amines and four of these functional groups make up the chelating ligand EDTA. The Jones reagent turns primary alcohols into these functional groups, which are reacted with alcohols in the Fischer esterification. For 10 points, name this functional group with formula “C-O-O-H.” ■END■