Which one of the following is a benzenoid aromatic compound? A) Furan B) Thiophene C) Pyridine D) Aniline E) Cyclopentadienyl anion
Hint: To be a benzenoid aromatic compound, the compound should have a benzene ring. Identify the compound having a benzene ring. Eliminate the options by calculating the number of carbons also. For instance, Furan is a five membered ring .
Complete answer: The benzene molecule contains 6 carbon atoms and 6 hydrogen atoms. 6 carbon atoms form a ring in which alternate single and double bonds are present. The structure of benzene is as shown below:
A benzenoid aromatic compound has benzene rings in its structure. Examples of benzenoid aromatic compounds include naphthalene, anthracene, phenanthrene, aniline etc. A non benzenoid aromatic compound contains conjugated pi electron systems with a ring of 5 to 7 carbon atoms. The aromatic character of non benzenoid aromatic compounds is due to the presence of alternate single and double bonds in cyclic conjugated systems. Examples of non benzenoid aromatic compounds include furan, thiophene, pyridine, etc.
Write the structures of different compounds given in the options.
Of the above compounds, only aniline contains a benzene ring. Hence, aniline is a benzenoid aromatic compound.
Thus, the option D is the correct option.
Note: Do not fail to differentiate between aromatic compounds and benzenoid compounds. Aromatic compounds include benzenoid aromatic compounds and non benzenoid aromatic compounds.