Standard caption

Standard titres, fixals ^[1] , primary standards - sets of chemical reagents , manufactured by industry in sealed ampoules . These ampoules contain a precisely known amount of substance.

To prepare the solution, the ampoule is broken using a special striker, its contents are quantitatively transferred to a volumetric flask and diluted with water to the required volume (up to the mark on the flask), which makes it possible to obtain a standard solution of the exact concentration . The resulting solution is used in titrimetry as a titrant or to determine the concentration of another titrant.

The substances used for the preparation of standard titres are subject to the following requirements: they must be clean, stable when stored at room temperature and must not absorb moisture and carbon dioxide. Standard titres are prepared for substances such as potassium permanganate , potassium dichromate , sodium chloride , oxalic acid , hydrochloric acid , silver nitrate , nitric acid .