Question 1

Which of the following statements best explains why benzene does not undergo addition reactions with bromine under normal conditions, but does react in the presence of an iron catalyst?

Accepted Answer

The iron catalyst generates a stronger electrophile, allowing benzene’s pi electrons to attack and form a sigma complex.

Question 2

Which of the following is the correct sequence for the mechanism of electrophilic aromatic substitution (EAS) in benzene?

Accepted Answer

Attack of electrophile, formation of sigma complex, loss of proton

Question 3

Which of the following substituents is a strongly activating, ortho/para-directing group in electrophilic aromatic substitution?

Accepted Answer

$$-OH$$

Question 4

In the iodination of 4’-hydroxyacetophenone using green chemistry, which combination of reagents is used to generate the electrophilic iodine species?

Accepted Answer

Sodium iodide and sodium hypochlorite (bleach)

Question 5

Which of the following best describes the effect of an electron-withdrawing group (EWG) on the reactivity and regioselectivity of a benzene ring in EAS?

Accepted Answer

Decreases reactivity and directs substitution to meta position

Question 6

Why is the green chemistry approach for iodination of 4’-hydroxyacetophenone considered safer than the traditional method?

Accepted Answer

It avoids the use of hazardous oxidants like nitric acid, reducing toxic byproducts.

Question 7

Given the following groups on a benzene ring, which will dominate the directing effects in the iodination of 4’-hydroxyacetophenone?

Accepted Answer

The hydroxyl group (OH), an ortho/para-directing EDG

Question 8

Which of the following equations correctly represents the generation of molecular iodine ($$I_2) in $$the green iodination procedure?

Accepted Answer

$$2NaI + NaOCl \rightarrow I_2$ + NaCl + 2NaOH$$

Question 9

Which safety precaution is NOT recommended when working with 4’-hydroxyacetophenone and sodium hypochlorite in the lab?

Accepted Answer

Wearing shorts and sandals for comfort

Question 10

A student adds bleach too quickly to the reaction mixture during the iodination of 4’-hydroxyacetophenone. What is the most likely consequence?

Accepted Answer

The reaction may become uncontrollable, leading to side reactions or hazardous conditions.

Question 11

Which of the following is a correct statement about the waste disposal procedure for this experiment?

Accepted Answer

Liquid chemical waste must be placed in the hazardous waste jar in the dispensing hood.

Question 12

Which of the following best explains why aromatic compounds burn with a strong sooty yellow flame?

Accepted Answer

They contain a high carbon-to-hydrogen ratio.

Question 13

Which of the following is the major product of the iodination of 4’-hydroxyacetophenone under green chemistry conditions?

Accepted Answer

3-Iodo-4’-hydroxyacetophenone (iodine ortho to OH, meta to acetyl)

Question 14

Which of the following is NOT a property of aromatic compounds?

Accepted Answer

They undergo nucleophilic aromatic substitution more readily than electrophilic aromatic substitution.

Question 15

Which of the following best describes the role of sodium thiosulfate in the reaction workup?

Accepted Answer

It neutralizes excess oxidizing agents and safely removes residual iodine.

Question 16

A student forgets to acidify the reaction mixture after adding sodium thiosulfate. What is the most likely outcome?

Accepted Answer

The aryl iodide product will not precipitate efficiently.

Iodination of 4’-Hydroxyacetophenone: Electrophilic Aromatic Substitution and Green Chemistry

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