Quiz

QUIZ

1. How many carbon atoms and how many double bonds are there in the benzene ring?

a. Five carbon atoms and two double bonds b. Six carbon atoms and two double bonds c. Six carbon atoms and three double bonds d. Eight carbon atoms and three double bonds

Answer: c. Benzene is a simple six-carbon ring associated with three double bonds that resonate with one another in what is a relatively stable molecule.

2. Which carbon atoms in the benzene structure have resonance?

a. The first and second carbon atoms b. The first and fourth carbon atoms c. None of the carbon atoms d. All of the carbon atoms

Answer: d. Resonance exists between all of the bonds of the benzene molecule so that the entire molecule’s carbon atoms have resonance.

3. A benzene molecule is considered an ortho molecule. Where are the side chains located?

a. On the 1 and 2 carbon atoms b. On the 1 and 3 carbon atoms c. On the 1 and 4 carbon atoms d. On the 1 and 5 carbon atoms

Answer: a. There is an ortho, meta, and para system that dictates where the side chains are located. The 1, 2-carbon side chains on the benzene molecule indicate an ortho configuration.

4. Benzene with a methyl group attached to it is called what?

a. Xylene b. Toluene c. Phenol d. Benzonitrile

Answer: b. Toluene is a benzene molecule that has a methyl group attached to it. This is one of the benzene derivatives that needs to be memorized.

5. Which molecule is least likely to comply with IUPAC nomenclature as a common name that also becomes an IUPAC name?

a. Phenol b. Benzoic acid c. Benzaldehyde d. Trinitrotoluene

Answer: d. The term trinitrotoluene is not preferred in the IUPAC nomenclature as it needs to be written out, rather than referring to it as TNT. The others have been adopted by the IUPAC system as names that can be used to describe benzene derivatives.

6. Benzene is a stable molecule because it has aromaticity; it is what shape and has what bond angles between carbon atoms?

a. Planar with 120-degree angles b. Planar with 109.5-degree angles c. Tetrahedral with 109.5-degree angles d. Tetrahedral with 120-degree angles

Answer: a. The molecule is planar with a 120-degree angle between carbon atoms, making benzene a very stable molecule.

7. What type of reaction is most preferred when an aromatic compound undergoes a reaction?

a. Addition b. Subtraction c. Nucleophilic addition d. Electrophilic Substitution

Answer: d. The preferred reaction is an electrophilic substitution reaction, which does not involve the loss of aromaticity. Any reaction that would threaten the aromaticity of the compound does not easily occur.

8. In making nitrobenzene, you need an electrophilic substance to add to the benzene molecule. What electrophilic substance is added to benzene in the nitration process?

e. HNO2 f. NH3 g. HNO3 h. NH4+

Answer: c. Nitric acid will be electrophilic, adding an NO2 molecule to benzene with the help of sulfuric acid, leading to the benzene molecule with an NO2 side chain or nitrobenzene.

9. The Friedel-Crafts reaction involves the addition of what side chain to benzene?

a. Halide b. Nitric oxide c. Sulfonic acid d. Alkyl side chain

Answer: d. The Friedel-Crafts reaction involves the addition of an alkyl side chain to a benzene molecule.

10. What is an appropriate catalyst in the Friedel-Crafts reaction?

a. Sulfuric acid b. Nitric acid c. Aluminum chloride d. Ammonium acetate

Answer: c. Aluminum chloride acts to cause a positive partial charge on an alkyl chloride molecule, resulting in the alkyl group being attached to the benzene molecule via electrophilic substitution. An end product is HCl.