Solution
Core Logic
Step 1: Reaction of Alcohols with PCl₅ CH₃CH₂CH₂-OH + PCl₅ arrow CH₃CH₂CH₂Cl + POCl₃ + HCl Thus, the by-product X is POCl₃.
Step 2: Elimination (Dehydrohalogenation) CH₃CH₂CH₂Cl alc. KOH, Δ CH₃CH=CH₂ (Y) (Propene)
Step 3: Anti-Markovnikov Addition (Peroxide effect) CH₃CH=CH₂ HBr, (CH₃COO)₂ CH₃CH₂CH₂-Br (Z) (1-Bromopropane)
Step 1: Final Conclusion
Therefore, X = POCl₃ and Z = CH₃CH₂CH₂Br.
Pattern Recognition
PCl₅ yields POCl₃, whereas PCl₃ yields H₃PO₃. HBr with peroxide is Kharasch effect (Anti-Markovnikov addition), placing the Bromine on the less hindered terminal carbon.
Chapter Mix
Class 12 Chemistry: Alcohols, Phenols and Ethers Class 12 Chemistry: Haloalkanes and Haloarenes