Consider a planar, completely conjugated monocyclic hydrocarbon monocation containing n carbon atoms. If this species is aromatic according to Hückel's rule, which of the following is a possible value for n ?

Step-by-step solution

For a completely conjugated monocyclic hydrocarbon monocation with n carbon atoms, one carbon atom bears a positive charge (contributing 0 -electrons) and the remaining (n-1) carbon atoms participate in -bonding. Thus, the total number of -electrons is (n-1) . According to Hückel's rule, for the species to be aromatic, the number of -electrons must be equal to (4k + 2) , where k is a non-negative integer ( k = 0, 1, 2, ). Equating the two: n - 1 = 4k + 2 n = 4k + 3 Checking the given options: If k = 1 , n = 4(1) +