Question

1. A TLC experiment is performed to separate a mixture of the compounds shown below. Label each chemical with the appropriate letter based off the TLC data. (2 points) • B OCH 2. What would happen to the Rivalues for your compounds if 30:70 hexane:acetone were used as the developing solvent instead of 70:30 hexane:acetone? Briefly explain why. (2 points) 3. After first using 90:10 hexane:acetone as the solvent, we switched to 70:30 hexane:acetone. Why did we not use 70:30 hexane:acetone from the start? Why did we not use 90:10 hexane:acetone the entire time? (2 points)

Answer 1

Q2) Rf of A,B and C will decrese due to decrese in the polarity of mobile phase on moving from 70:30 to 30:70(Hexane /Acetone ratio).

1. A TLC experiment is performed to separate a mixture of the compounds shown below. Label each chemical with the appropriate letter based off the TLC data. (2 points) TO-CH3

Q3) To establish the polarity of mobile phase needed for effective seperation, we start with less polar (90:10; Hexane/acetone) mobile phase to more polar (70:30; Hexane/acetone).This is to ensure that first less polar compound like C(Benzene) comes out first follwed by more polar A and B. Instead if we start with more polar combination like (70:30; Hexane/acetone), all the compounds like A,B and C will come together and there will be no seperation. Besides, if we use (90:10; Hexane/acetone) mobile phase throughout, the seperation time will be too long and as more polar compounds like B and C will not move that much with this less polar solvent system.