THE IRON(II) INDUCED-OXIDATION OF CHLORIDE BY PERMANGANATE

Fe(II) and other reductants were titrated with MnO4 and with compounds of manganese with oxidation states intermediate between (II) and (VII ), in the absence and presence of most of the additives recommended to prevent the oxidation of Cl- ions induced by titrating. Fe(II) with M nO4- in solutions containing HCl. The results obtained indicate that M n(V) and/or (VI) are the most probable oxidizing intermediates respons ible for the oxidation of Cl- ions. The inhibiting effect of Mn(II) fr om the Z.R reagent and of Ce(III) can be explained by their preferenti al oxidation by the intermediate. Borax and sodium acetate are active by raising the pH, while the decrease of the oxidation of Cl- ions in the presence of ligands such as F and PO43- can be attributed to compl ex formation with Fe(III), what makes Fe(II) a stronger reductant.