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

Options

A.
B.
C.
D.

Answer

C

Explanation

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.