Solving a chemistry problem

1. 10 liters of industrial room air containing hydrogen chloride were passed through 20.0 ml of water in an absorption vessel, after which 5.00 ml of the resulting solution was taken into a test tube for nephelometry using the scale method. At the same time, a series of standard solutions was prepared by adding V ml of KCl solution (T = 0.01023 mg/ml) to the same test tubes. The same volume of HNO3 and AgNO3 was added to all test tubes, the volume was brought to 10.0 ml, mixed, and after 10 minutes the turbidities of the test and reference solutions were compared. Determine the concentration of HCl (mg/m3), if equality of turbidity was observed at the following values of V?
OPTION 1
V, ml 0.50