Application Of Complexometric Titration Pdf UPD Download
an analytical technique based on the chemical process of titration is the complexometric titration [ 13, 14 ]. the chemistry of titration involves the formation of a complex between an acidic or a basic compound and an ion, which is in excess of the stoichiometric amount. the ionic complex is stable and can be dissolved in a suitable solvent. the ions are transferred to the solution of the complexing agent as a soluble salt. any free acidic or basic compound that is present in the analyte is neutralized or is present as a soluble salt in the solution. the method is based on the principle of the reaction below:
application of complexometric titration pdf download
the method of the titration of mercury or lead with a base is the same as that of a colorimetric test. in the titration of mercury, the excess base removes the hydroxide ions from the surface of the silica, which results in liberation of the cationic form of the metal. this cation can then be detected by the usual method for detecting cations, namely titration with silver nitrate [ 15 ]. lead can be detected by taking advantage of the fact that the hydroxide of lead is more soluble in alkaline solutions than the chloride of lead. an excess of base, say caustic soda, releases the lead hydroxide, which can be detected colorimetrically using methylthymol blue [ 16 ].
the method of the titration of calcium and magnesium with a base is the same as that of a colorimetric test. it involves the complexation of the metal ions with excess base and then the de-complexation of the ions by the addition of tartaric acid and naf respectively [ 17 ]. the reaction is very simple, rapid and requires no complexing agent. the concentrations of calcium and magnesium in the silica sample are determined by flame photometry [ 18 ].