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Which of the following annulenes is aromatic? a.[8]annulene b.[10]annulene C.[12]annulene d.none?
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Which of the following annulenes is aromatic? a.[8]annulene b.[10]annu...
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Introduction:
An annulene is a cyclic compound composed of conjugated double bonds. The aromaticity of annulenes can be determined using Hückel's rule, which states that a compound will be aromatic if it possesses a fully conjugated system with 4n+2 π electrons, where n is an integer.

Aromaticity:
Aromatic compounds have unique stability due to their delocalized π electrons, which are evenly distributed over the entire conjugated system. This stability arises from the molecular orbital theory and the resonance energy associated with aromatic compounds.

[8]Annulene:
[8]Annulene has a total of 8 π electrons, making it a non-aromatic compound according to Hückel's rule. The π electron count does not satisfy the 4n+2 rule, where n is an integer. Therefore, [8]annulene is not aromatic.

[10]Annulene:
[10]Annulene has a total of 10 π electrons, which satisfies Hückel's rule. The π electron count of [10]annulene is 4n+2, where n=2. Therefore, [10]annulene is aromatic.

[12]Annulene:
[12]Annulene has a total of 12 π electrons, which does not satisfy Hückel's rule. The π electron count of [12]annulene is 4n, where n=3. Therefore, [12]annulene is not aromatic.

Conclusion:
Among the given options, only [10]annulene is aromatic according to Hückel's rule. [8]annulene and [12]annulene do not satisfy the 4n+2 rule and are therefore non-aromatic.
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Which of the following annulenes is aromatic? a.[8]annulene b.[10]annu...
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Can you explain the answer of this question below:On the basis of aromaticity, there are three types of compounds i.e. aromatic, non-aromatic and antiaromatic.The increasing order of stability of these compounds are is under:Anti-aromatic compound non-aromatic compound aromatic compounds. Compounds to be aromaticfollow the following conditions (according to valence bond theory)(i) The compounds must be be cyclic in structure having (4n + 2) e, where n = Hckels number = 0, 1,2, 3 et.c(ii) The each atoms of the cyclic structure must have unhybridised p-orbital i.e. the atoms of thecompounds have unhybridised p-orbital i.e. usually have sp2 hybrid or planar.(iii) There must be a ring current of electrons in the ring or cyclic structure i.e. cyclic structure mustundergo resonance .Compounds to be anti-aromatic, it must have 4ne where n = 1, 2 and it must be planar and undergoresonance. Non-aromatic compounds the name itself spells that compounds must be non-planarirrespective of number of electrons. Either it has 4ne or (4n + 2) electrons it does not matter.The rate of reaction of any aromatic compounds depends upon the following factors:(i) Electron density(ii) stability of carbocation producedHigher the amount of electron density of the ring, higher will be its rate towards aromatic electrophilicsubstitution and vice-versa. Similarly, higher will be the stability of the produced carbocation after theattack of electrophile, higher will be its rate towards aromatic electrophilic substitution. There is a greateffect of kinetic labelling on the rate of aromatic electrophilic substitution. As we known that higher theatomic weight or, molecualr weight, higher will be the van der Waals force of attraction or, bond energy.Since there will be effect of kienetic labelling if the 2nd step of the reaction will be the slow step, (r.d.s.)otherwise there will be no effect of kinetic labelling.Q. Which of the following is correct order of the rate of reaction of C6H6, C6D6 and C6T6 towardsnitrations?A:C6H6 C6D6 C6T6B:C6H6 = C6D6 = C6T6C:C6H6 C6D6 = C6T6D:C6T6 C6D6 C6H6The answer is b.

On the basis of aromaticity, there are three types of compounds i.e. aromatic, non-aromatic and antiaromatic. The increasing order of stability of these compounds are is under: Anti-aromatic compound < non-aromatic compound < aromatic compounds. Compounds to be aromaticfollow the following conditions (according to valence bond theory)(i) The compounds must be be cyclic in structure having (4n + 2)π e–, where n = Hückel’s number = 0, 1, 2, 3 et.c(ii) The each atoms of the cyclic structure must have unhybridised p-orbital i.e. the atoms of the compounds have unhybridised p-orbital i.e. usually have sp2 hybrid or planar.(iii) There must be a ring current of π electrons in the ring or cyclic structure i.e. cyclic structure mustundergo resonance .Compounds to be anti-aromatic, it must have 4nπe– where n = 1, 2… and it must be planar and undergo resonance. Non-aromatic compounds the name itself spells that compounds must be non-planarirrespective of number of π electrons. Either it has 4nπe– or (4n + 2) π electrons it does not matter.The rate of reaction of any aromatic compounds depends upon the following factors:(i) Electron density(ii) stability of carbocation producedHigher the amount of electron density of the ring, higher will be its rate towards aromatic electrophilic substitution and vice-versa. Similarly, higher will be the stability of the produced carbocation after the attack of electrophile, higher will be its rate towards aromatic electrophilic substitution. There is a great effect of kinetic labelling on the rate of aromatic electrophilic substitution. As we known that higher the atomic weight or, molecualr weight, higher will be the van der Waal’s force of attraction or, bond energy. Since there will be effect of kienetic labelling if the 2nd step of the reaction will be the slow step, (r.d.s.) otherwise there will be no effect of kinetic labelling.Q. Which of the following is correct order of the rate of reaction of C6H6, C6D6 and C6T6 towardssulphonation?

Which of the following annulenes is aromatic? a.[8]annulene b.[10]annulene C.[12]annulene d.none?
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Which of the following annulenes is aromatic? a.[8]annulene b.[10]annulene C.[12]annulene d.none? for JEE 2024 is part of JEE preparation. The Question and answers have been prepared according to the JEE exam syllabus. Information about Which of the following annulenes is aromatic? a.[8]annulene b.[10]annulene C.[12]annulene d.none? covers all topics & solutions for JEE 2024 Exam. Find important definitions, questions, meanings, examples, exercises and tests below for Which of the following annulenes is aromatic? a.[8]annulene b.[10]annulene C.[12]annulene d.none?.
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