77. Solving a chemistry problem

71. A surfactant dissolved in water is adsorbed on the mercury-water surface according to the Langmuir equation. At a surfactant concentration of 0.3 mol/l, the degree of surface filling θ is 0.6. Calculate the surface tension at the mercury-solution interface at 298K if the surfactant concentration is 0.2 mol/l. Take the limiting value of the area occupied by a surfactant molecule on the surface equal to 0.2 nm2, interfacial tension at the mercury-water interface σ0= 0.373 J/m2.