Consider the following list of carbocations: (I) Tropylium cation (II) p -Methoxybenzyl cation (III) m -Methoxybenzyl cation (IV) p -Methylbenzyl cation (V) p -Nitrobenzyl cation (VI) Cyclopropenyl cation Find the total number of carbocations from the given list that are thermodynamically MORE stable than the unsubstituted benzyl cation ( C ₆ H ₅ CH ₂^+ ).

Step-by-step solution

The stability of the given carbocations is compared with the unsubstituted benzyl cation ( C ₆ H ₅ CH ₂^+ ): (I) Tropylium cation: It is a 7-membered aromatic ring with 6 electrons. Aromaticity makes it exceptionally stable, more so than the benzyl cation. (II) p -Methoxybenzyl cation: The -OCH ₃ group at the para position exerts a strong +M effect, which stabilizes the carbocation more than the unsubstituted benzyl cation. (III) m -Methoxybenzyl cation: At the meta position, the +M effect of -OCH ₃ does not operat