How many π MO's does the following compound have?

Question

Quizplus · Accepted Answer

The compound given is a hexatriene, which contains six carbon atoms and three double bonds. The number of π MOs can be calculated using the formula 4n+2, where n is the number of conjugated double bonds. In this case, n=3, so the number of π MOs is 4(3)+2=14. However, since the molecule is symmetric, two of those orbitals will be non-bonding (i.e. they will have zero electron density in the middle of the chain), leaving a total of 12 π MOs. Half of those MOs will be bonding and half will be antibonding. Therefore, the correct answer is C, which represents the closest number of π MOs to 12.

How Many π MO's Does the Following Compound Have