Organic Chemistry

1. State true or false a) While visualizing the chromatogram, you can directly look at the UV light. b) The Iodine jars should not be removed from the hoods. c) Since the unknown solutions used in this experiment are analgesic drug mixtures, it is

not a big concern if some solution spills on my hands.

2. TLC separates compounds based on their ………………

3. List three factors on which the retardation factor (Rf) of a compound depends on.

• • •

4. What is the purpose of using a piece of filter paper in the TLC developing chamber during this experiment?

5. In experiment 3A, you will compare the Rf values of o-hydroxy-acetophenone and p- hydroxy-acetophenone. Which compound do you think will have the greater Rf value?Justify your answer.

O

OH

O

OH

o-hydroxy- acetophenone

p-hydroxy- acetophenone

6. Arrange the following compounds in the increasing order of Rf.

a)

b) Br

c) COOH

d)

O

O

7. Write the equation for calculating Rf. Calculate the Rf values for the two spots A and B.

1

2

3

4

5

A B

8. Where should you properly dispose of a) Used TLC capillaries? : b) Used TLC plates? :

9. Suppose you performed acetylation of ferrocene (see reaction scheme). You monitored the reaction using TLC and made the following observations. [Note: Acetyl group (Ac) is polar]

Reaction Scheme:

Fe Fe Fe Ac Ac

Ac

O

O

O

H3PO4

Major Product

Unwanted Side Prpduct

+

R O

Ac =

Observations:

At t = 0 min

At t = 15 min

At t = 30 min

What is the optimum time to stop the reaction and why? [3 points]