Question

Describe the alkyne you would start with and the reagents you would use if you wanted to Synthesize

a. Pentane. b. Cis-2-butene. c. trans-2-pentene. d. 1-hexene.

Short answer

1. H₂ in presence of Pd/C becomes strong reducing agent and form primary alkane from alkyne.

2. H₂ in presence of lindlar catalyst stops the reaction at alkene stage.

3. Na/NH₃cannot be used to reduce terminal alkynes, because Na will remove the hydrogen that is attached to the sp carbon of the terminal alkyne.

Step-by-step solution

Some conclusions

1. H₂ in presence of Pd/C becomes strong reducing agent and form primary alkane from alkyne.

2. H₂ in presence of lindlar catalyst stops the reaction at alkene stage.

3. Na/NH₃cannot be used to reduce terminal alkynes, because Na will remove the hydrogen that is attached to the sp carbon of the terminal alkyne.

Final answer

So the final reactions are-