0731. Solving a chemistry problem

272. To determine the Cu(II) content in the presence of Fe(III), copper was first separated on a cation exchanger in the H+ form. 5 ml of the test solution was added to the chromatographic column. To extract copper, the column was washed with 0.5 M HCl solution and the solution was placed in a 250 ml volumetric flask. We took 25 ml of the resulting solution and added it to a 50 ml volumetric flask, added 15 ml of 25% ammonia, made up to the mark with water and measured the optical density. To construct a calibration graph, 2.0 was placed in volumetric flasks with a capacity of 50 ml; 5.0; 10.0; 15.0 ml of copper sulfate solution with copper titer 1. 10-3 g/ml, added 15 ml of 25% ammonia, brought to the mark with water and measured the optical density of standard solutions:
V, ml 2.0 5.0 10.0 15.0
Ast 0.05 0.15 0.30 0.45
Determine the concentration (mg/ml) of copper in the analyzed solution for the following options:
Problem No. 272
Ah 0.36