NCERT Solution
Class 11
Chemistry
Hydrocarbons
explain why the following systems are not aromatic...

Question:
Explain why the following systems are not aromatic?

Answer:

(i) For the given compound, the number of π-electrons is six. But only four π-electrons are present within the ring. Also there is no conjugation of π-electrons within the ring and the compound is not planar in shape. Hence, the given compound is not aromatic in nature.

(ii) For the given compound, the number of π-electrons is four. By Huckel's rule,

4n + 2 = 4

4n = 2

n = ½

For a compound to be aromatic, the value of n must be an integer (n = 0, 1, 2…), which is not true for given compound. Hence, it is non aromatic in nature.

(iii) For the given compound, the number of π-electrons is eight. By Huckel's rule,

4n + 2 = 8

4n = 6

n = 3/2

For a compound to be aromatic, the value of n must be an integer (n = 0, 1, 2…). Since the value of n is not an integer, the given compound is not aromatic in nature.

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Question:
Explain why the following systems are not aromatic?

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Question:
Explain why the following systems are not aromatic?