137. Задачка по химии №013 705

Construct a surface tension isotherm b = f (C) from the results of measuring the surface tension of aqueous solutions of isobutyric acid (C5H10O2) at the boundary with air at 293 K.
Concentration C * 102, mol / L 0 0.78 1.56 3.125 6.25
Surface tension b, mN / m 71.5 70.0 68.3 65.3 60.7
Concentration C * 102, mol / L 12.5 25.0 50.0 100.0
Surface tension b, mN / m 54.3 47.3 39.6 31.8
Calculate surface activity.