1-Hexyne is treated with sodium hydride, followed by bromoethane. Lindlar hydrogenation of the resulting product affords what final product?

1. Deprotonation of 1-Hexyne:

   • 1-Hexyne (CH≡C-CH₂-CH₂-CH₂-CH₃) is treated with sodium hydride (NaH).
   • Sodium hydride acts as a strong base and deprotonates the terminal alkyne, forming the acetylide anion (CH≡C⁻-CH₂-CH₂-CH₂-CH₃).

2. Alkylation with Bromoethane:

   • The acetylide anion (CH≡C⁻-CH₂-CH₂-CH₂-CH₃) reacts with bromoethane (CH₃-CH₂-Br).
   • This results in an SN2 reaction where the acetylide anion attacks the carbon bonded to the bromine, displacing the bromide ion.
   • The product of this reaction is 1-octyne (CH≡C-CH₂-CH₂-CH₂-CH₂-CH₃).

3. Lindlar Hydrogenation:

   • 1-Octyne (CH≡C-CH₂-CH₂-CH₂-CH₂-CH₃) is subjected to Lindlar hydrogenation.
   • Lindlar's catalyst selectively hydrogenates alkynes to cis-alkenes.
   • The final product is cis-1-octene (CH₂=CH-CH₂-CH₂-CH₂-CH₂-CH₃).

Therefore, the final product is cis-1-octene.