question_answer

Which of the following is the most stable, and which is the next most stable isomer?

(I)	(II)
(III)	(IV)

A) \[III>I\]               

B) \[I>III\]               

C) \[IV>III\]              

D) \[II>I\]

Correct Answer: A

Solution :

[a] (Both have conjugated system) In (II) \[3\alpha -H\] atom but have isolated system. In (IV) \[2-\alpha -H\] & conjugated system but strained ring due to \[(C=\,=C)\] bond outside ring. \[\therefore \]    stability order: \[III>I>II>IV\]