1) A student measured the melting point of Compound X and compared it to a list of possible known compounds. The student narrowed down the list of possibilities to Compounds A, B, and C (all of which had similar melting points). The student developed a TLC plate using an appropriate eluant, in order to observe the relative Rf s of each of the compounds. The outcome is illustrated below:

Which of the following statements is most true:

1. Compound C appears to be less polar than Compound X

2. Compound A is not the same as Compound X

3. Rf values provides supporting evidence that Compound B might be Compound X

4. Compound A is more polar than compound X

5. All of the above are true.

2.A student produced the following TLC using Hexane: Ethyl acetate (90:10) as the mobile phase

To repeat the experiment and get a higher Rf value, the student should

a) spot more sample on the TLC plate

b) use hexane as the mobile phase

c) use Hexane: Ethyl acetate (70:30) as the mobile phase

d) use a longer time to allow the solvent to migrate further up the plate.

SOLVENT FRONT ORIGIN Compound A Compound B Compound C Unknown Compound X SOLVENT FRONT ORIGIN Unknown Compound X