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EEJ MAIN Chemistry QUESTION #7128
Question 1
Which of the following reagent systems is specifically used to produce trans-alkenes from the reduction of alkynes?
  • $H_{2}$ with $Pd/C$ and $BaSO_{4}$
  • $NaBH_{4}$
  • $Na$ in liquid $NH_{3}$✔️
  • $Sn$ and $HCl$
Correct Answer Explanation
The reduction of non-terminal alkynes using sodium ($Na$) or lithium ($Li$) in liquid ammonia ($NH_3$) follows a free-radical mechanism that leads to the formation of the more stable trans-alkene (Birch reduction). Conversely, Lindlar's catalyst ($H_2, Pd/C, BaSO_4$) would yield a cis-alkene.