Question

Give the structures of both 1,2 and 1,4 adducts resulting from reaction of 1 equivalent of hcl with 1,3-pentadiene

Answer 1

1,3-pentadiene has two double bonds which are conjugated, which undergo electrophilic addition reaction on reacting with $HCl$.

The structure of 1,3-pentadiene is shown in the image.

When strong acid such as $HCl$ reacts with 1,3-pentadiene, the electrophilic addition reaction can occur either on double bond at 1,2-position or at 3,4-position. The reaction that occurs is shown in the image.