Explanation: The structure of Hexanenitrile is CH₃CH₂CH₂CH₂CH₂CN or C₅H₁₁CN. To convert Hexanenitrile into 1-aminopentane, first we need hexanamide (amide group-RCONH₂) and we can get hexanamide from hexanoyl chloride (acid chloride group – RCOCl) and we can get hexanoyl chloride from hexanoic acid.

Step 1: Convert Hexanenitrile into Hexanoic acid

Hexanenitrile (C₅H₁₁CN) undergoes hydrolysis to form Hexanoic acid (C₅H₁₁COOH)

Step 2: Convert Hexanoic acid into hexanoyl chloride

Hexanoic acid (C₅H₁₁COOH) reacts with thionyl chloride (SOCl₂) or PCl₅ or PCl₃ to form hexanoyl chloride (C₅H₁₁COCl) by the replacement of OH group by Cl atom.

Step 3: Convert Hexanoyl chloride into hexanamide

Hexanoyl chloride (C₅H₁₁COCl) reacts with excess ammonia to form hexanamide (C₅H₁₁CONH₂) by the removal of NH₄Cl.

Step 4: Convert hexanamide into 1- amino pentane by Hoffman Bromamide reaction)

Hexanamide (C₅H₁₁CONH₂) is treated with an aqueous or ethanolic solution of potassium hydroxide (KOH) and bromine (Br₂), it gives 1-aminopentane (final product) which has one carbon atom less than the hexanamide.