Question

The-correct stability order for the following species is :

• A. $\left(II\right)>\left(IV\right)>\left(I\right)>\left(III\right)$
• B. $\left(I\right)>\left(II\right)>\left(III\right)>\left(IV\right)$
• C. $\left(II\right)>\left(I\right)>\left(IV\right)>\left(III\right)$
• D. $\left(I\right)>\left(III\right)>\left(II\right)>\left(IV\right)$

Answer 1

The correct option is D $\left(I\right)>\left(III\right)>\left(II\right)>\left(IV\right)$

Carbocation of structure I has positive charge ob the carbon surrounded by three alkyl groups which are electron donating $+I$ inductive effect and it is stabilized by lone pair of electrons on $O$ atom so it is highly stable. Structure III has positive charge on C with two alkyl group and $O$ atom. In II form Carbocation carbon has two alkyl $+I$ effect and the least stable is the carbon with positive charge on terminal carbon with single carbon atom.