In this Chromatography experiment, what material is the stationary phase? What a

Question

In this Chromatography experiment, what material is the stationary phase? What are the two different mobile phases? Use the two Chromatograms below the answer the questions that follow: In the 80% Acetone in Water chromatogram, which ion. Cl^- or I-. is more strongly attracted to the mobile phase? Briefly explain your reasoning. Calculate the R_f values for the F^-, Cl^-. Br^- and I- ions using 80% acetone in water. Calculate the Rf values for the components in the Unknown using 80% acetone in water. Which two halide ions are present in the unknown? When using the 20% Acetone in Water, are the Halides more strongly attracted to the Stationary Phase or the Mobile Phase? Briefly explain your reasoning.

Explanation / Answer

1) stationary phase is the silica on which the solute is adsorbed, mobile phase is the solvent system we are using in the TLC chamber .(acetone + water)

2)

a) in TLC the compound which stays at the bottom means is more polar and is strongly adsorbed, this actually means the solvent system is trying to retain Cl- more than teh I- .

b) Rf = didtance travelled by solute / distance travelled by solvent

F- = 0/ 25 =0

Cl- = 10/25 = 0.4

Br- = 15/25 = 0.6

I- = 20/25 = 0.8

c) unknown

Rf(lower) = 10/25 =0.4

Rf (upper) = 20/25 = 0.8

d) hence from Rf values of teh halodes we can clearly say that the two halides present are Cl- and I-

e) since water is more polar than acetone ... and the TLC is clearly showing that the solutes are more attracted towards the mobile phase... than stationary phase.

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