Draw the condensed structural formula for each of the following:
a. trans-1-bromo-2-chloroethene

Question

Draw the condensed structural formula for each of the following:

a. trans-1-bromo-2-chloroethene

Accepted Answer

Hi, welcome back everyone. Our next question says, what is the structure of the following trans 23, Di Chloro two beine. And we have four different structures labeled A through D. And we'll look at them a little more closely after we work our way through what we expect this structure to be as we compare them to our calculated structure. So the first thing to do is look at the name of our longest carbon chain. In this case, that's Butane telling us it's a four carbon chain with a single, double bond and the two in there two. Butane tells us that the double bond goes from carbon two, two, carbon three. So first, let's draw that four carbon chain. The skeletal structure is often the easiest to do for this. And our answer choices are in the form of skeletal structures. So that will be good for comparing. So 1234 Carmens, I'm going to go ahead and number them to transfer my substituents and double bonds onto here. Again, I know my double bond is from carbon two to carbon three. So I'll put that right there in the middle of my molecule And so I can actually already eliminate one answer choice because choice A shows the double bond from carbon one to carbon two on my chain. So choice A has the double bond in the wrong location. Each of my other three choices shows the double bond in the middle. Now we need to put on our substituents. We have two chlorine on carbons, two and three. So we'll put them all in here. Went to erase my numbers two and three to make a little more space there, put on the chlorine. But now we need to double check because we're told that they're in the trans arrangement. So let's make sure that corresponds with our structure. As we recall, the trans arrangement is when the similar substituents or the same substituents are on opposite sides of the double bond. So in this case, uh the easiest way to look at, we have our two chlorine and two metals. And we indeed see that the two metals are on opposite sides of the double bond and then the two chlorine are on opposite sides of the double bond. So this correctly is the trans arrangement. So that would correspond to choice D which shows a four carbon chain, the double bond in the middle and chlorine on carbons two and three opposite from each other. Let's look at choices B and C just to understand why they're incorrect. In choice B, the two chlorine are on the same side of the double bond. So this would be the sis arrangement. Why Choice B is incorrect? And in choice C, the chlorine are on carbons one and two. So they're in the wrong location, which is why Choice C is incorrect. This might confuse you a little bit because the chorines are on the same carbon. But that's not what cis and trans is about cis and trans. You're talking about substituents on the two different carbons of the double bond, but whether they're on the top or bottom of the double bond. So once again, our correct answer here is choice D with the double bond in the middle and then the chlorine on opposite sides of it on carbons two and three. See you in the next video.

Draw the condensed structural formula for each of the following:
a. trans-1-bromo-2-chloroethene

Verified video answer for a similar problem:

Key Concepts

Condensed Structural Formula

Geometric Isomerism

Nomenclature of Organic Compounds