EFFECT OF PHENOLS ON THE POLAROGRAPHIC AND SPECTRAL BEHAVIOR OF HEXAVALENT MOLYBDENUM IN SULFURIC-ACID-SOLUTIONS

The polarographic and spectral behaviour of hexavalent molybdenum in s ulphuric acid solutions have been studied in the absence and presence of phenols. The processes of reduction pass ultimately to trivalent mo lybdenum via two to four reduction waves depending on the acid and the phenol concentrations. The presence of resorcinol or pyrogallol cause s the reduction waves to split or intermingle due to the surface activ ity of the phenols. In the presence of high concentrations of pyrogall ol, the sulphate complexes transform into the pyrogallol complex. Also , these phenols cause the polymerization of the monomer molybdenum spe cies. The nature and the kinetic parameters of the waves in different media have been investigated.