Hey Briana,
Here's the answer to this question from our Subject Expert Samantha:
Several of these above reactions have the possibility of forming E/Z mixtures.
Hydrohalogenation can form E/Z isomers if the reaction is carried out on an internal alkyne. This reaction on terminal alkynes will not form E/Z isomers because you'll end up with two hydrogens on the carbon that was the terminal one.
Hydrohalogenation with Peroxides will form E/Z isomers in any situation (both internal and terminal alkynes).
Halogenation of alkynes using only 1 equivalent of X2 reagent will result in a mixture of E/Z isomers.
All of these situations come about due to the possible ways that molecules can approach each other in the transition state of the various mechanisms.
Replied on Practice Exam: Properties of Alkenes and Reactions of Alkenes
07 Nov 10:25
You're very welcome Suzy!