Identify a final product obtained when Pent-3-enenitrile is treated...

The structure of Pent-3-enenitrile is $CH_3-CH=CH-CH_2-CN$.

DIBAL-H ($\text{AlH}(i\text{-Bu})_2$) is a selective reducing agent. It reduces nitriles to imines, which upon subsequent acid hydrolysis yield aldehydes. It does not reduce isolated carbon-carbon double bonds.

Therefore, the $-CN$ group is converted to a $-CHO$ group, while the double bond remains intact.

$CH_3-CH=CH-CH_2-CN \xrightarrow[2. H_3O^+]{1. \text{DIBAL-H}} CH_3-CH=CH-CH_2-CHO$

The final product is Pent-3-enal.

Answer: Pent-3-enal