Question

c) III d) IV e) None of these choices 1) Which of h llwng would you espet to be aromaic IV b) II c) III d) IV e) All of these choices 12) Which of the following would you expect to be aromatic? IV non non c) III d) IV e) All of these choices. 13) Which of the following would you expect to be aromatic? IV a) I b) II

Answer 1

11.)Only (I) follows Huckel (4n+2) rule because it contains 2 pi electrons where n =0.the pi electrons are conpetely delocalized.Therefore (a) is the correct answer.

(II) does not contains any pi electrons .Therefore it is not aromatic.

(III) contains a pi bond but this pi bond is not delocalised and therefore does not follow Huckel aromaticity rule.

(IV) contains 6 pi electrons but it conatins a sp3 hybridised carbon in the ring and therefore the electrons are not completely delocalised. Hence it is not aromatic.

12.) (a) is the correct answer.This is because it contains 2 pi electrons which are completely delocalized and follows huckel rule.Others given species do not follow Huckel rule and therefore they are not aromatic .

13.) (c) is the correct answer.

Both (I) and (II) contain only four pi electrons which do not obey Huckel rule of aromaticity.(III) contain 6 delocalised pi electrons and follows Huckel aromaticity rule.(IV) does not follows Huckel aromaticity rule.