| 摘要 |
To carry out the process, chemicals of analysis quality are used, and the water employed is doubly distilled in a quartz appts. The pH measurements are carried out with a Radiometer (RTM) meter calibrated with 0.05 M solns. of potassium biphthalate (pH 4.01 at 25 deg.C). - The titrations are effected using burettes comprising 50 ml. plastic bottles in the stoppers of which plastic tubes of 2 mm. are fitted, bent through somewhat more than 90 deg., and drawn out to a point. - The vessel in which the titrations are carried out is of glass with a dia. of approx. 2.5 cms. and a height of approx. 5 cms. Approximately 0.02 M Hg(NO3)2- soln. is used, and sufficient hydrochloric acid or sodium chloride soln. is measured out so that 4-5 drops of mercury nitrate soln. are required for each titration. The indicator soln. is produced by dissolving 0.5 g. of diphenylcarbazone and O.05 g. of bromthymol blue in 100 ml. 90% ethanol. |
