Problem 2.1:
Which of the following pairs are resonance structure? For pairs that are
resonance structures, use the curved-arrow formalism to derive the second
structure from the first.
Figure W.1: Problem 1
Problem 2.2:
One of the resonance structures of phenanthrene, a hydrocarbon found
naturally in coal tar, is shown below. It turns out that this is only one
of five resonance structures that can be drawn for this compound.
(a) Using the curved-arrow formalism to aid you, find the other four resonance
structures of phenanthrene (fill in the incomplete structures).
Figure X.1: Problem 2
(b) Assuming that each resonance structure contributes equally to the final
resonance hybrid of phenanthrene, identify the longest bond and shortest
bond in phenanthrene and give their respective bond orders.
