Hydrohalogenation of Alkynes Quiz

What is a key difference between the hydrohalogenation of alkynes and alkenes?

• Alkynes have one pi bond, while alkenes have two.

• Alkynes can undergo hydrohalogenation twice, while alkenes can only do so once.

• Alkynes and alkenes have identical hydrohalogenation processes.

• Alkenes require more reagent equivalents than alkynes.

In the hydrohalogenation of alkenes, what is formed in the first step?

• A peroxide

• A free radical

• A carbocation

• A stable alkene

What is the result of Markovnikov addition in alkenes?

• No addition occurs.

• Bromine adds to the less substituted side.

• Hydrogen adds to the more substituted side.

• Hydrogen adds to the less substituted side.

How does the substitution of terminal and internal alkynes affect hydrohalogenation?

• Terminal alkynes are more reactive than internal alkynes.

• Markovnikov and anti-Markovnikov addition are not applicable to internal alkynes.

• Internal alkynes always undergo anti-Markovnikov addition.

• Substitution does not affect hydrohalogenation.

Why is the mechanism of hydrohalogenation of alkynes considered uncertain?

• It is a well-understood first-order process.

• It involves a stable carbocation.

• There may be multiple competing mechanisms.

• It always follows a single, known pathway.

What is a characteristic of the carbocation formed during alkyne hydrohalogenation?

• It is less stable than a primary carbocation.

• It is as stable as a secondary carbocation.

• It is more stable than a primary carbocation.

• It is not formed at all.

What happens when HBr is used with peroxides in alkyne hydrohalogenation?

• It results in anti-Markovnikov addition.

• It results in Markovnikov addition.

• It prevents any addition from occurring.

• It forms a stable alkene.

What is the effect of adding two equivalents of HBr with peroxides to an alkyne?

• It results in Markovnikov addition twice.

• It results in a single addition.

• It results in no addition.

• It results in anti-Markovnikov addition twice.

What is the role of peroxides in the hydrohalogenation of alkynes?

• They promote anti-Markovnikov addition.

• They have no effect on the reaction.

• They inhibit the reaction.

• They promote Markovnikov addition.

What is the result of adding one equivalent of HBr with peroxides to a terminal alkyne?

• No reaction occurs

• Formation of an alkene with Markovnikov addition

• Formation of an alkene with anti-Markovnikov addition

• Formation of an alkane