1-Phenyl-2-butene has an ultraviolet absorption at max = 208 nm ( = 8000). On treatment with...

Question:

1-Phenyl-2-butene has an ultraviolet absorption at λ _max = 208 nm (ε = 8000). On treatment with a small amount of strong acid, isomerization occurs and a new substance with λ _max = 250 nm (ε = 15,800) is formed. Propose a structure for this isomer, and suggest a mechanism for its formation.