Rapid Volumetric Method for the Determination of Elementary Carbon by the Decomposition with Iodic Acid. II

In the indirect determination of carbon by estimating the iodine-evolved in the reaction of elementary carbon and iodic acid (Preceedingl Report), an improvement of the apparatus was made for the accurate determination and the good results were obtained. Tests on the kinds of strong phosphoric acid to be used were carried out. By the use of the strong phosphoric acid prepared by dehydration of orthophosphoric acid of the density 1.75 until its temperature reached about 300°C and by means of this improved apparatus, the rapid and accurate determination of graphite became possible. Since it was found that, in the case of the strong phosphoric acid of lower concentration, only graphite showed lower rate of oxidation, a separate determination of crystalline carbon and amorphous carbon was attemped by using Torthophosphoric acid of the density 1.75 and an approximately identical result was obtained by using an equal-amount mixture of activated carbon:and graphite or acetylene black and graphite.