85. Solving a chemistry problem

49. To determine the concentration of HF, the dependence of the electrical conductivity χ on the acid content in the solution is used:

CHF, mol/l 0.004 0.007 0.015 0.030 0.060 0.121 0.243
χ *104, Ohm-1*cm-1 2.5 3.8 5.0 8.0 12.3 21.0 36.3

Construct a calibration graph based on these data in the coordinates lg χ -lgCHF and use it to determine the concentration of hydrofluoric acid if its electrical conductivity is equal to:
Options a b c d e
χ *104, Ohm-1*cm-1 3.2 9.2 14.4 20.1 28.2