Question

Based on your knowledge of molecular geometry, which hypothesized structure of Benzene has bond angles strained well beyond known tolerances?

Answer 1

It seems that the question is lacking hypothesized structures, which are provided in Figure A

Answer:

Option A has bond angles that have the highest strain beyond known tolerance

Explanation:

Note: Please find the complete question in the attachment

The hypothesized structures in the options were the proposed structures of benzene in the mid 19th century by Ladenburg (1869), Thiele (1899), Armstrong (1887), and Kekule (1865) respectively

Option A suggests sp3 hybridization of the carbon atom. sp3 hybridized atoms are oriented at 109.5° to be stable. The structure suggests that bond angles between C-C bonds are 60° and 90°, these bond angles are well beyond the known tolerable angle strain.

Options B and D (currently accepted structures of benzene) are sp2 hybridized and their bonds angle is 120°, which is the optimal angle for sp2 hybridized atom. Option C also suggests sp2 hybridized carbon, so their will also be no ring strain in it. But it is not an accepted structure as it was suggested to contain radical like properties by Armstrong.