Friday, January 9, 2009

Aromatic Hydrocarbons - Benzene - Conceptual Questions

1. What are aromatic hydro carbons?
2. Describe the characteristics of benzene?
3. What is the common system of nomenclature of aromatic hydrocarbons?
4. What is the IUPAC system of nomenclature of aromatic hydrocarbons?
5. Explain the stability and structure of benzene.
6. What is enthalpy of hydrogenation and what is the relevance of this concept to benzene?
7. Explain position isomerism in arenas?
8. What are the criteria for aromaticity?
9. What is Huckle rule?
10. What are the sources of aromatic carbons?

11. Explain the following methods of preparing benzene and its homologues

i. From alkynes
ii. From phenol
iii. From diazonium salts
iv. From aryl halides
v. From Grignard reagent
vi. By decarboxylation of aromatic acids
vii. Using Friedel Craft’s reaction

12. What are physical properties of benzene and other aromatics?

13. Explain the following chemical reactions or properties of aromatics?

A. Substitution reactions
i. halogenation
ii. Sulphonation
iii. Nitration
iv. Alkylation and acylation (Friedel-Crafts Acylation)

B. Addition reactions
i. Addition of hydrogen
ii. Addition of halogens
iii. Addition of ozone

C. Oxidation reactions
i. Combustion
ii. Oxidation of benzene
iii. Oxidation of alkyl side chain

14. Explain the reaction mechanism of electrophilic substitution reactions of benzene.
15. Explain the role of catalysts in the reaction mechanism of electrophilic substitution reactions of benzene.
16. What is directive influence of substituents in benzene compounds?
17. What is the explanation of different directive influence?
18. What are activator groups?
19. What are deactivating groups?
20. What is effect of substituents on reactivity?
21. What are rules for determining orientation in di-substituted benzenes?
22. Write short notes on polynuclear hydrocarbons
23. Explain the carcinogenicity and toxicity of polynuclear hydrocarbons.

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