Which of the following carbocation is expected to be most stable ?

1.	Which of the following carbocation is expected to be most stable ?
Answer» Solution :Since `-NO_(2)` GROUP is electron-withdrawing, therefore, presence of a +ve CHARGE on the carbon atom which is attached to `-NO_(2)` group makes the carbocation UNSTABLE. Thus, carbocations (B) and (d) are destabilized. Carbocation (a) is also destablized because in one of its resonating structures shown below, +ve charge is present on the carbon atom to which `-NO_(2)` group is attached. Thus, carbocation (a) is also destabilized. CONSEQUENTLY, carbocation (c) is expected to be most stable since in more of its resonating structures, +ve charge moves to that carbon which is attached to `-NO_(2)` group. Thus, option (c) is correct.

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