140. Solving a chemistry problem

IV. When determining NaCl in sodium hydroxide solution, a series of standard solutions were prepared. For this, V (ml) of a NaCl solution (TNaCl = 0.1000 g / ml) was transferred into volumetric flasks with a capacity of 25.0 ml, the reagents necessary to obtain a suspension of AgCl were added, the apparent optical densities were measured using a nephelometer and the following data were obtained - table 12.
Table 12

V, ml 0.3 0.5 0.8 1.5
Akazh 0.67 0.55 0.39 0.15

A 21.74 g sample of the analyzed solution was neutralized with HNO3, transferred to a volumetric flask, and 50.0 ml of a solution was prepared, VA (ml) of which was used to prepare 25.0 ml of AgCl suspension. Determine the mass fraction (%) of NaCl according to the following data - table 13 (in accordance with the task number).
Table 13

VA task number, ml Akaj
55 2.0 0.48