n order to assess the factors that impact the fate and behavior of the antibiotic chlortetracycline in soil, an adsorption isotherm study was conducted. Five-gram samples of high-organic-matter surface soil or low-organic-matter subsurface soil were equilibrated with 30 mL volumes of solution containing varying initial concentrations (cin) of the antibiotic. The suspensions were equilibrated for 24 h and the solid and solution phases separated by centrifugation. The solution was then analyzed by HPLC for chlortetracycline to yield equilibrium concentrations (ceq). The results are presented in the following table. Answer the following: a. On a single graph, plot the chlortetracycline adsorption isotherms for both soils. b. For each isotherm, answer the following: i. What are the isotherm types? ii. What adsorption model(s) should be employed to offer a quantitative characterization of the isotherms? iii. Fit the adsorption data with the appropriate adsorption isotherm model(s) and generate the adsorption constants. iv. Why might the isotherms for the surface and subsoils samples differ (which soil adsorbs the greatest amount of the antibiotic and why)? Initial (cin) and Equilibrium concentrations (ceq) (mol L1) of Chlortetracycline in Solutions in Contact with Surface and Subsurface Soil Samples Equilibrium concentration Initial concentration Surface Subsurface 9.86 0.031 0.010 19.89 0.039 0.013 38.58 0.066 0.018 86.84 0.162 0.032 170.97 0.358 0.076