So let's go ahead and look into the first one. And the first one is a hydrohalogenation of an alkyne. Now a hydrohalogenation, remember, is just an HX with a triple bond. Well, if I were to react that one time, I would expect to get a Markovnikov halogen added. But it turns out that if you react this twice with alkynes, what you're going to end up getting is actually geminal dihalides. Now remember that the word "gem" stands for geminal, and that means that they're both on the same carbon. So let's go ahead and see how this works.
If I were to react this with one equivalent, I would expect it to look like this, with a positive charge here and an H here. Okay? And then that positive charge would grab, or I'm sorry, the X would grab the positive charge and I would get my intermediate, my first product. Okay? But if I expose it to more than one equivalent, for example, let's say that I exposed it to 2 equivalents total, then it could react again. So then I would get this double bond attacking the H, kicking out the X. What I would end up getting is a carbocation that now looks like this, where my X is there, my H is there. And once again, I would get my X. And now, by the way, there are 2 H's there. And now my X would attack there again. So what I would end up getting is a product that looks like this where I have a 5-membered ring with 2 X's in the Markovnikov position. Okay. So it's the geminal dihalide part and it's the Markovnikov part.
And then I would have 2 H's that came from my addition reaction. Okay? I know you're wondering, well, what about that carbon? Shouldn't it have 3 H's? Shouldn't it be CH3? Yeah. Well, that H was always there though. That kind of looks messy. I'm just going to redraw that. That H was always there because that's the H that was originally on that triple bond anyway. I'm just saying that through this reaction, we end up adding H twice and X twice. Does that make sense? I hope so. I hope that it flows. It's really not a complicated reaction as long as you know what hydrohalogenation is. Okay?
