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According to huckel's rule,n=1 in benzene but n indicates no. of pi bonds and benzene has 3 pi bonds,so how is n=1?? P.S.-Please do tell me if I went wrong somewhere and the reason too!

According to huckel's rule,n=1 in benzene but n indicates no. of pi bonds and benzene has 3 pi bonds,so how is n=1??
P.S.-Please do tell me if I  went wrong somewhere and the reason too!

Grade:12th pass

5 Answers

Arnab Saha
43 Points
7 years ago
Huckels rule states that a planar yclic compound is aromatic if the number of electrons involved in resonance is 4n+2. In benzene there are 3 pi bonds and each pi bond is composed of 2 electrons. Now all pi bonds and hence 3×2=6 ( I.e. 4×(1)+2) electrons are involved in resonance. Therefore it is aromatic.
Aishwarya Byreddy
14 Points
7 years ago
Yeah but how are you taking n=1 for benzene??????                                                                                                             By what means are you estimating the n value?????????
Arnab Saha
43 Points
7 years ago
I`m not exactly taking n=1 for benzene. But instead, I`m simply saying that the total number of electrons involved in the resonance of benzene is 6 and when we put n=1 in 4n+2 we get 6 which satisfies the condition for aromatic its according to heckles rule.
Aishwarya Byreddy
14 Points
7 years ago
I just wanna know what exactly “n” means! I understood what you said but I just wanna know what the letter indicates.!
Arnab Saha
43 Points
7 years ago
N is just a random variable. It doesn`t signify anything alone. If you put different integral values of n from 0 onwards in 4n+2 you get the number of electrons needed for aromaticity which in the afore mentioned case is 1. For example...if 4 pi bonds are involved in resonance then 8 electrons are involved. But 8 doesn`t satisfy 4n+2 for any integral value of n. So the compound isn`t aromatic

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