Convert each of the following line-angle formulas to a condens...

Question

Convert each of the following line-angle formulas to a condensed structural formula and give its IUPAC name: (11.3)

a.

Accepted Answer

Hi, everybody. Let's take a look at our next problem. It says give the condensed structural formula for the line angle formula shown below and provide its Iupac name. So we have a line angle structure or a skeletal structure drawn for us. And then we have four possible answer choices. They are all correctly condensed structural formulas where bonds are shown to show how the atoms are connected. So dash is used for the bonds but groups of carbons and hydrogens group together in the format of say ch three dash CH two. And then each choice has a different Iupac name. This is important because if you are on a test and speed matter to you, it means that only one of these can be the correct Iupac name. So you don't even need to worry about the structure. You can go straight for the correct name here. So we're doing this as a sample problem. So we'll work through the structure as well. But you're going to find your right answer just by using the Iupac name in this case. So let's look at our skeletal structure. We have a choice here. We have several, it sort of looks like three branches coming together at a single point. So when we name something, we start with, find the longest chain of carbons. So here we have several options. It's three chains coming together. So our longest chain will encompass two of them with one being named as a branch. And there's two ways of numbering these encompassing two branches obviously with one as a side branch. So if I glance over all at these, I can see kind of from looking over it that the chain on the left is a little shorter than the two chains on the right, which are equally equal length. So that will tell me that I should use the two equal length longer chains together as my longest chain. So I'm going to start numbering my carbons. I want to number them in a way. So I'll say number to make the first substituent the lowest possible number. So if you can, you can usually number your chain from either end, obviously. So you want to number in a way that that number will be the lowest possible for your first substituent. In this case, my branch is right in the middle. It doesn't matter which direction I start. So I'll start at the top carbon 1234, an average carbon five where my branch comes off and 6789. So my longest chain is nine carbons. So I'll just put equals nine carbons next to where I wrote find the longest chain. So it didn't matter which order I number them in. Now, let's think about what the name is of that chain. I have nine carbons. My prefix will be non 49 and then I have no double bonds or triple bonds, no other special functional groups. So I use a ane. So it's a non a, a nine carbon chain with all single bonds. Now, we want to look at name are substituent. So we need to look at that. So we'll say name B branch. In this case, our branch has two carbons, 12. So it excuse me, it has three carbons. That's what's tricky with the line structures. You always have to remember that the ends of them are carbon atoms as well. So 1 to 3 carbons on our branch. So that's going to give me the name Propol for my branch. It doesn't have any branching itself. It's just a straight three carbon chain and I need to give it its substituent number which is five. So I use a hyphen five hyphen prop na name. So let's look for my answer, which gives that as a name. So choice A, I have four butyl octane, but that assigns the carbons in the wrong way. And in fact, I suspect that would be the result if I numbered in the opposite way because since my Propol group has only three carbons, while my long chain is made up of 24 carbon chains, or I should say a four carbon and a five carbon depending on how I look at that. Then if I numbered my chain, 12345 on one of the longer chains and then 678, onto what I call the propol group, that would give me an eight carbon main chain, which would be octane. And then my branch would be 1234, a beetle branch. So this Iupac name in choice A would be a result of wrong longest chain, we'll call it. So we'll go ahead and eliminate. Choice. A choice. B says five prole nona. So I've got the correct answer here. I'll go ahead and choose choice B so I said that's because I have the only, every single answer choice is a different name. Choice C says five Ethel name. The location is correct. The longest chain is correct. The branch name is incorrect. Ethel has only two carbons, but my chain has three. But you saw how easy it is to make that mistake. I originally said two carbons, forgetting that that end of the line is also a carbon. So just one thing to be careful for with these line structures. So choice C also incorrect. And in melo choice D it is 11 dibutyl butane. Well, again, this results in picking the wrong longest chain. It's referring to the shorter chain, the one on the left as the main chain of four carbons and then the two symmetrical chains as being branches. But that's forgetting that you can join two of these chains and count all the way through to nine carbons. So it's just a result of kind of looking at this in the wrong way. That's why choice D isn't correct. So that first step of finding your longest chain is definitely crucial here and easy to get a little mixed up with. Now, we'll just double check my condensed structural condensed structural formula. So I should have nine carbon groups, either CH three or if they're internal CH two. So I do indeed have 123456789 carbons in the main chain. And Choice B written straight across. And then we see a line down from the fifth carbon with a three carbon chain for my Propol branch. The other way I could indicate this is by putting this in parentheses after my fifth carbon, but that can get a little confusing. This is a little easier to see. So the condensed structural formula with the OPEC name for the line structure provided is Choice B have our structural formula there nine carbons across in the main chain with three carbons in the branch. And its IUPAC name is five propal nona. See you in the next video.

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Convert each of the following line-angle formulas to a condensed structural formula and give its IUPAC name: (11.3)
a. <IMAGE>

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Struggling with GOB Chemistry?

Convert each of the following line-angle formulas to a condensed structural formula and give its IUPAC name: (11.3)a. <IMAGE>

Watch next

Naming Alkanes with Substituents practice set

Convert each of the following line-angle formulas to a condensed structural formula and give its IUPAC name: (11.3)
a. <IMAGE>