0730. Solving a chemistry problem

3. Quantitative determination of the drug “Natrii chloridum” according to FS 42-2572-95 is carried out as follows: about 1 g of the drug (exact mass) is dissolved in water in a 50 ml volumetric flask and the volume of the solution is adjusted to the mark with water. 10 ml of the resulting solution is diluted with water to 40 ml and titrated with a 0.1 mol/l solution of silver nitrate until it turns orange-yellow (indicator is potassium chromate).
Sodium chloride in terms of dry matter should be at least 99.5% in the preparation.
Give a rationale for this quantification method. Write the reaction equations. Calculate the mass fraction of the drug as a percentage if the sample of the powder being analyzed is 1.0178 g; weight loss on drying 0.46%; Mm. sodium chloride 58.44; the volume of silver nitrate solution used for titration is 8.7 ml. Based on the data obtained, make a conclusion about the compliance of the sample under study with the requirements of the FS.