question_answer

The increasing order of dehydration of following is  

A)  \[I<II<II<IV\]

B)  \[II<III<IV<I\]

C)  \[I<III<II<IV\]

D)  \[I<IV<II<III\]

Correct Answer: A

Solution :

 Dehydration of IV is most facile since it gives an aromatic compound. Dehydration of III gives a conjugated diene which is stabilized by resonance. Dehydration of II gives only cyclohexene which is not stabilized by resonance. In contrast, phenol (I) does not undergo dehydration. Thus, the increasing order of dehydration is: \[I<II<III<IV\].