Chemistry - GOC Question with Solution | TestHub

To find the total number of resonating structures for the triphenylmethyl cation (${P{h}_{3}C}^{\oplus }$), we consider the independent Kekulé forms (2 forms per neutral benzene ring) along with the position of the positive charge:

Charge on the central carbon: All three phenyl rings remain neutral and intact. Each ring can independently exist in 2 Kekulé forms, giving $2\times 2\times 2=8$ structures.

Charge delocalized into a ring: There are 3 choices for the ring carrying the charge. Within that ring, the charge can occupy 3 positions (2 ortho, 1 para), while the other 2 neutral rings each have 2 Kekulé forms, giving $3\times 3\times (2\times 2)=36$ structures.

Total Resonating Structures: Adding both cases together gives $8+36=44$.