Organic Chemistry

1. State true or false a) To achieve good separation of the components of a mixture by column

chromatography, a difference in Rf value of at least 0.2 is required. b) Greater the height of the column, better the separation of components of the mixture.

2. How will you ensure tight packing of the contents of the column while packing?

3. While performing column chromatography, why is it important to not let the column dry?

4. How will you monitor the progress of the column chromatography of a colorless sample?

5. (a) In this experiment, you are trying to isolate ferrocene and acetylferrocene from their mixture. Which one will elute from the column first and why?

(b) How will you determine the purity of the compounds you isolated? What will you do if they are not pure?

6. You have a mixture of naphthalene, o-hydroxyacetophenone and p- hydroxyacetophenone. Supposing you picked an appropriate solution gradient to elute all of the components from an alumina column, in what order would you expect them to elute?

H3C O

OH

H3C O

OH

Naphthalene (A)

o-Hydroxyacetophenone (B)

p-Hydroxyacetophenone (C)

7. Suppose you have a mixture of three different compounds and you want to separate the mixture into their pure constituents. You checked the TLC of the mixture in different solvent compositions and made the following observations. (ether is non-polar solvent, MtBE is polar solvent)

8:2 5:5 2:8 (ether:MtBE) (ether:MtBE) (ether:MtBE)

PTO (a) Which solvent scheme will be best used for column chromatography and why?

(b) After running the column, you realized that you have not resolved (separated) compounds B and C. How will you separate them? Which solvent system will you use?