Hydrogenation and Alkynes Concepts

Professor Dave explains the hydrogenation of alkynes, detailing methods to convert alkynes to alkanes and alkenes. He discusses using palladium for full hydrogenation to alkanes, Lindlar catalyst for Z alkenes, and lithium or sodium for E alkenes. The video includes practical examples and emphasizes the importance of stereochemistry in synthetic pathways.

What is the primary outcome when hydrogen is added over palladium to an alkyne?

• Formation of a Z alkene

• Formation of an alkane

• Formation of an E alkene

• Formation of an alkene

Which catalyst is used to stop hydrogenation at the alkene stage, specifically forming Z alkenes?

• Sodium catalyst

• Lithium catalyst

• Lindlar catalyst

• Palladium catalyst

What type of alkene is produced when using a Lindlar catalyst?

• E alkene

• Z alkene

• Cis alkene

• Trans alkene

Which metals are used to produce E alkenes from alkynes?

• Copper and zinc

• Iron and nickel

• Lithium and sodium

• Magnesium and calcium

What is the role of alkali metals in the hydrogenation of alkynes?

• To fully hydrogenate to alkanes

• To stop at the alkene stage and form E alkenes

• To form Z alkenes

• To prevent any hydrogenation

Which method results in the complete conversion of an alkyne to an alkane?

• Using lithium and ethyl amine

• Using hydrogen over palladium

• Using sodium and ammonia

• Using Lindlar catalyst

What is the IUPAC name of a 5-carbon alkyne used in the example?

• 2-Pentyne

• 1-Pentyne

• Pentene

• Pentane

In the example, what is the product when hydrogenation is done over palladium?

• E-Pentene

• 2-Pentyne

• Pentane

• Z-Pentene

What is the stereochemistry of the alkene formed using Lindlar catalyst in the example?

• Cis configuration

• Z configuration

• E configuration

• Trans configuration

What is the final product when sodium and ammonia are used in the example?

• 2-Pentyne

• E-Pentene

• Pentane

• Z-Pentene