Part 7 : MECHANISM

The following diagram shows the solution to the mechanistic question. Note that all the information applies to a single reaction sequence that has been completely described verbally.  There is no need for extra reagents or extra steps etc. The curly arrows are drawn specifically to match the text in the question. The biggest problem students have is making sure they understand the language of chemistry. Most students have trouble because they can't draw the structures from the IUPAC names. Read the words carefully, and then make the curly arrows tell that same story.  Remember curly arrows go from electron rich to poor and to balance the charges at each step.

(a)
reaction of bromopentadiene with water
(b)
resonance of pentadienyl cation

(c)  Note the similarity of this answer to that in part (a)

formation of 2,4-pentadien-1-ol

(d) They are constitutional isomers as they have different names (the locants are different).

If you struggle with this type of question, first draw the compounds whose names are provided (if you can't then review your nomenclature) then think about the types of reactions (e.g. acid / base) and try to fill in the structures in the gaps, then finally add the required curly arrows to account for all the bonding changes.