Fall 2009 Name: Date: Experiment 3.7A&B: Solvent and Polarity Effects in Thin-Layer Chromatography Part A Solvent Front (mm) Solvent trans-stilbene (mm) Rf vanillin (mm) vanillyl alcohol (mm) Rf Rf Hexane Ethyl acetate Acetone Part B Solvent System __________________________ Solvent Front (mm)___________ trans-stilbene vanillin (mm) (mm) Rf Rf Unknown Number _________ vanillyl alcohol Unknown(s) (mm) (mm) Rf Rf value(s) Unknown(s) _____________________________________________ Rank the solvents and compounds in order of increasing polarities. Rank 1 (least polar) 2 3 (most polar) Solvent Compound Fall 2009 A solvent that gives a high Rf value is said to have a high eluting ability. Rank the solvents in terms of eluting ability for each of the three compounds. Rank Trans-stilbene Vanillin Vanillyl alcohol 1 (lowest) 2 3 (highest) 1. Do polar or non-polar solvents have greater eluting ability? Explain using observations above. For each of the solvents used, rank the compounds (trans-stilbene, vanillin, vanillyl alcohol) in terms of increasing elution rate (increasing Rf value). Solvent Compound with lowest Rf Compound with intermediate Rf Compound with highest Rf Hexane Ethyl Acetate Acetone 2. Does the order of elution vary according to solvent polarity? Explain using observations above. 3. Do polar or non-polar analytes travel faster on silica gel? Explain using observations above.