2-hexyne gives trans-2-hexene on treatment with:

• (A) Pt/H₂
• (B) Li/NH₃
• (C) Pd/BaSO₄
• (D) LiAlH₄

To convert 2-hexyne to trans-2-hexene, the best choice is:

Answer

(C) Pd/BaSO₄

Explanation

Palladium on barium sulfate (Pd/BaSO₄) is a catalyst used in the partial hydrogenation of alkynes. This method selectively adds hydrogen across the triple bond, resulting in the formation of the trans isomer of the alkene.

Other Options

• (A) Pt/H₂: This would typically lead to the formation of a mixture of cis and trans alkenes.
• (B) Li/NH₃: This is used for the reduction of alkynes to trans alkenes, but it does not specifically yield trans-2-hexene from 2-hexyne.
• (D) LiAlH₄: This is a strong reducing agent that would reduce the alkyne to an alkane rather than forming an alkene.

Thus, for the specific formation of trans-2-hexene from 2-hexyne, Pd/BaSO₄ is the most suitable choice.