Student C needs to separate two compounds from one another and runs a columns. H
ID: 1070929 • Letter: S
Question
Student C needs to separate two compounds from one another and runs a columns. He then calls you over and explains that running his columns, he collected 5 fractions, and the shows you the TLC of the fractions from the columns, Consider the following scenarios: Student C loaded his sample onto the column diluted with too much solvent. Would this scenario lead to the above TLC result? Yes or No. Why? Student C used too nonpolar an eluent system when running the column. Would this scenario lead to the above TLC result? Yes or No. Why? Student C used too polar an eluent system when running the column. Would this scenario lead to the above TLC result? yes or no. Why? Student C used too little adsorbent when running the column. Would this scenario lead to the above TLC result? Yes or No. Why? Student C added eluent prior to material being adsorbed into silica when running the column. would this scenario lead to the above TLC result? Yes or No. Why? Student C used a columns that had too large a diameter. Would this scenario lead to the above TLC result? Yes or No. Why?Explanation / Answer
A. yes, if the solvent used to dilute is reasonably polar. Otheriwse that would not be the case
B. No. Mere addition of non polar solvent would not have given such a tlc as that would separate considerably and does not yield the mixture
C. Yes. Addition of polar solvent would bring both the compounds down and hence the result would be a mixture
D. Yes. If the stationary phase is not long enough when dealing with a compounds that have close Rf values that would result a mixture
E. No. That is not the case
F. Yes. The diameter of the column choosen should be low for the mixture that have close Rf and of course that would depend on the amount of the sample being separated as well
E.