Question

1mixture of luorene 1. Chromatography Concept. Draw and name the structures of the two substances in today's Cuoreron sample. Remembering that hexane will be the first eluent, and the stationary phase is alumina, which of these two substances should we expect to come out of the column first? Defend Si02 your answer [30pts] Al2O3 2. Equipment Practicals. In preparing the chromatography column, you were strongly advised prevent the stationary phase from drying. Suggest why you don't want the column to dry out. [20pts] Equipment Practicals. When the column has been prepared and the sample has been added, you are advised to add a thin layer of sand on top of the column. What is the purpose of the sand? [10pt] 3. 4. Procedure In the column chromatography, after eluting with hexane, you are told to elute with a 1:1 hexane/diethyl ether mixture. Suggest a reason for this switch of eluents. [20pts 5. Equipment Practicals. In preparing the TLC chamber, you are advised to add the eluent to the beaker -and stick a piece of filter paper to the sides of the chamber. What purpose does the filter paper serve? [20pts]

Answer 1

Quus -1 sinu Hexane is NON POLAR Solvent for and Florene fworene Fluorenone is a also a NON Polar Relative to Huorenone So pluorene will have loose interaction with Stationary phase and will be elute out first Muoreno ne hawe Polar e=0St Bonds makes shong interaction with A1203: (Stallonauy Phuse) and will be elwred at and place guesa Fection awy phase should not be allowed to duy out complerley because Quacks well form within aluca column i Pt duies and compounds can fall down Hauk instead of partitioning b/w mobile è atatten avey Phase. Ques-3 Purpose of sand Sand at top and even loading of sample sample diffuses even huo ugh band without aand Dle would be added directly to aſilica and would stick where we # is added y nor evenly avross awyau o alica

SS. Que3-4 while first elwing with NON Polar Solucent ig adusable not to suddenly chonge the Polarity g solvent ise mixture of (olal + Non Polau ? Showd be used otherwise cacks will duelo p in Wloumn le cracking of coloumn will occur. Ques-s filter paper alt alsoules the liquid in solvent and puowdes mou aula fou evaporasten - bie Barwarion of Solvent molecules in air inside TLC Chamber.