(••••) LOOKING AHEAD Bromination of buta-1,3-diene with a single equivalent of Br₂ can give either of two products. (a) Which of these products (A or B) would you predict to be more stable? Justify your answer.

All right. Hi, everyone. So the given question says that when one equivalent of BR two reacts with 23 dimeo beta, 13 dien, two alkene products are formed, determine which alkene is more stable. And why? So here, right, the question mentions that both of our products are going to be all keys. And specifically, we're con we're comparing the relative stability of one over the other. So let's recall a couple of factors that determine the stability of alkenes. Number one is substitution around the double bond. Or in other words, right, the number of R groups connected to your double bond increases a stability number two is conjugation. So if you have at least two pi bonds that are separated by one single bond, they're said to be in conjugation and that creates more stability. The third factor is geometry and that looked a little wonky. So let me just fix that. But geometry specifically refers to whether or not the alkene in question is in the C or the trans configuration because recall that trans alkenes are more stable than cys all keens due to reduced straight or STAIC effects. And the fourth and final factor is ring strain. When you're talking about a cyclo, I'll keep right. So if you have a cyclone in a relatively small ring that creates very high ring strain that destabilizes the alkene overall. So let's go ahead and compare right now here. All Keen A, what you'll notice is that each sp two carbon of my All Keen has two other carbons bound to it, right. So in total, that's for our groups, which means that Keen A is tetra substituted. Now, by contrast, right, alkene B is a terminal alkene. So one sp two carbon has two hydrogens, whereas the other has two other carbons. So in total, that's two. Yes, that's two R groups and that makes A B die substituted. So here, right, according to the first factor, as you increase the amount of substitution around the double bond, the alkene becomes more stable. So when we compare a Tetris substituted to a di substituted alkene, the tetras substituted alkene is more substituted and therefore more stable. So here, right, to answer the question specifically, OK. A is more stable and the reason it's more stable is due to a higher degree of substitution around the double bond. And there you have it, right, Keen A is more stable due to a higher degree of substitution around the double bond. So with that being said, thank you so much for watching and I hope you found this helpful