An anionic surfactant with a 14-carbon chain in pure water at 25C has a surface tension () that can be modeled by the following equation where C is concentration in units of mol/L: = 72.2 15.9 ln(1 + (2.764 104)C)

a) Determine the efficiency (pC20) of the surfactant. b) If the surface tension of a solution of this surfactant with a concentration of C = 0.25 mol/L is measured to be 29.0 mN/m, estimate the CMC of the surfactant c) If the surfactant above were exchanged for the 16-carbon member of the same series, describe how the surface tension data would change and give a numerical estimate of the new pC20 value