Question

Do you expect hexatriene `C_6H_8` to have multiple resonance structures?

Answer 1

Yes, hexatriene has multiple resonance structures.

Explanation:

The structure of hexa-1,3,5-triene is

(from www.chemsynthesis.com)

We can draw many resonance contributors for hexatriene.

`"CH"_2"=CH-CH=CH-CH=CH"_2 ⟷ stackrel(-)("C")"H"_2"-"stackrel(+)("C")"H-CH=CH-CH=CH"_2 ⟷ stackrel(-)("C")"H"_2"-CH=CH-"stackrel(+)("C")"H-CH=CH"_2 ⟷ "etc."`

All but the first contributor have a separation of charge, so they are high-energy contributors and relatively unimportant.

Hexa-1,3,5-triene has only one important resonance contributor.