0730. Solving a chemistry problem

7. Quantitative determination of the drug “Calcii chloridum” according to FS 42-2567-00 is carried out as follows: about 0.8 g of the drug (exact mass), weighed in a closed bottle, dissolved in water, transferred to a 100 ml volumetric flask, adjusted to the volume solution with water to the mark and mix thoroughly. To 25 ml of the resulting solution add 5 ml of an ammonia buffer solution, 0.1 g of an indicator mixture or 7 drops of a dark blue acid chromium solution and titrate with vigorous stirring with a 0.05 mol/l solution of Trilon B to a blue-violet color. Give a rationale for this quantification method. Write the reaction equations. The calcium chloride content in the preparation was 99.0%. Weight of the analyzed drug is 0.7949 g; Mm. calcium chloride 219.08. Calculate the volume of a 0.05 mol/L solution of Trilon B, which will be consumed during the quantitative determination of the drug.