Benzene is described as aromatic because it
Correct answer: D. is planar, cyclic and has a delocalised system of six pi electrons obeying Huckel's rule
- A. has a pleasant smell
- B. contains only carbon and hydrogen
- C. reacts readily by addition
- D. is planar, cyclic and has a delocalised system of six pi electrons obeying Huckel's rule
Explanation
Aromaticity in the modern sense requires a planar cyclic conjugated system containing 4n plus 2 pi electrons, which for benzene means six, and this confers exceptional stability. The word originally referred to the smell of such compounds, which is why the first option is the historical but chemically wrong answer. Aromatic compounds characteristically undergo substitution rather than addition.
Report an error
The more specific you are, the faster it gets fixed. A source beats an opinion.
Prefer email? support@testustad.com
About Benzene and Aromatic Compounds
Benzene has a planar ring of delocalised π electrons, giving aromatic stability and equal carbon-carbon bond lengths. The topic covers resonance, electrophilic substitution reactions such as nitration, halogenation, sulphonation and Friedel-Crafts reactions, along with substituent effects and the distinction between substitution in benzene and addition in ordinary alkenes.
Practise Chemistry of Hydrocarbons
1,091 free Chemistry of Hydrocarbons MCQs from Chemistry, each with the correct answer and an explanation. Unlimited attempts, no account needed.
Discussion
Stuck on an option, or know a faster way to get there? Ask or explain it here.
No comments yet. Be the first to explain this one.
Exams that ask Chemistry questions like this
Chemistry is on 14 papers prepared for on TestUstad, and all of them draw the same bank, so this question is worth knowing for every one of them.
More Benzene and Aromatic Compounds questions
The nitration of benzene is carried out using
Benzene undergoes electrophilic substitution rather than addition because substitution
The Kekule structure of benzene failed to explain
Which one of the following is not a characteristic of benzene?
Chlorination of benzene in the presence of iron (III) chloride involves mechanism of:
Benzene gives mainly_________?