Sample pre-lab quiz for the Electrophilic Aromatic Substitution experiment.

1) The following two compounds are placed on a chromatography column and eluted with a moderately polar solvent. What is the order of elution of the two compounds?

  1. di-t-butylbenzene will elute first
  2. acetophenone will elute first
  3. the two compounds will not separate and will elute at the same rate
  4. neither compound will elute

2) A Friedel-Craft reaction is a type of:

  1. nucleophilic substitution
  2. addition reaction to alkenes
  3. electrophilic aromatic substitution
  4. acid-base reaction

3) The limiting reagent in the following reaction is:

 Compound MW bp mp density misc.
ferrocene 186 249 172 ........  
acetylferrocene 228 ........ 81-83 ........  
diacetylferrocene 270 ........ 125-7 ........
acetic anhydride 102 139 -73 1.08  
phosphoric acid 98 158 ........ 1.68 den. given is for 85% soln of phosphoric acid in water: this is the conc. of phosphoric acid used in the exp.

  1. ferrocene
  2. acetic anhydride
  3. phosphoric acid

4) Alkyl groups attached to aromatic rings:

  1. are deactivating
  2. are activating
  3. always cause polyalkylation
  4. none of the above

5) Consider the following developed TLC plate of standard ferrocene and a reaction mixture of ferrocene, phosphoric acid, and acetic anhydride sampled at 7 minutes and again at 15 minutes, Choose the correct answer from the multiple choices.

  1. a
  2. b
  3. c
  4. d

6) What product(s) would you expect to obtain from the following reaction?

7) A student isolated monoacetylferrocene from a microscale column as you will do in this experiment. He had some problems with the isolation. When he took a melting point, he found that the solid melted from 71-77 degrees C. His TA ran an NMR of his product (below). What can you conclude about his product?

  1. It is pure ferrocene.
  2. It is pure acetylferrocene.
  3. It contains acetylferrocene and ferrocene.
  4. It contains acetylferrocene and diacetylferrocene.

Answers.