Draw the condensed structural or line-angle formula if cyclic,...

Question

Draw the condensed structural or line-angle formula if cyclic, for each of the following:

b. 1,1-dibromo-2-pentyne

Accepted Answer

Welcome back everyone. Our next question says, what is the condensed structural formula of 22 di Chloro three hex? And we're given four different answer choices A through D with four different possibilities for this condensed structural formula. So we'll describe these in more detail as we look at our name and think about what the structure should look like. But at an overall glance, first, we make sure that these are indeed condensed structural formulas and all of them are, they have those lines indicating how atoms are attached. But the ch groups are indicated as letter groups without the individual ch bonds descript are delineated. So let's look at our compound name and think about what this structure should look like. So our root compound is a hex sign. So we see that Yne that tells us we have a triple bond and we have a hex sign. So we have a six carbon chain and then we see that it says three hex signs. So our triple bond must be from carbon 32 carbon four. So that's kind of the basic description of our chain. And then the beginning of the name says 22 die chloro. So we have two chlorine atoms on carbon too. So both of them on the same carbon. So with this information, we actually can take a quick sort of overall view of our four structures and probably eliminate some. So let's look quickly at choice. A first of all, even before we look specifically at choice, a just an overall glance will tell us that every single structure has a triple bond in it. So we're set for that. So now let's look at choice A, we see we have two chlorine atoms, but they are not on the same carbon, they're on two different carbons. So right away, we don't need to go any further. Don't need to check carbon numbers or how many are in the chain. We've got the chlorine on different carbons and we know they must both be on carbon too. So choice A incorrect. Then we look at Choice B and once again, here are two chlorine atoms are at either end of the chain. So at the first and last carbon, definitely not in the right place. They should both be on carbon too. So chlorine on wrong carbon. Choice B eliminated. Now let's look at choice C, we have two chlorine atoms on the second carbon. So it passes inspection that way. We hold that thought and look at choice D Well, choice D we have two chlorine atoms that are on the same carbon, but they are on the wrong carbon they're on. So two chlorine on carbon one. So it's the wrong carmen. So choice D is incorrect as well. So without having to go any further, pretty speedily, I've brought myself down to only one answer. Choice. Left. Choice C. So on a test at this point, I picked Choice C and keep going. I don't do any further work. But since this is a sample problem, we'll be thorough and look at this and make sure it's all correct. So we have our two chlorine on the second carbon in the chain. Let's check that we have the correct number of carmens. And then our triple bond is in the right place. So we start with CH three, our first carbon on the left which we label carbon one, then we come to carbon two which has two chlorine attached to it. Then carbon three as a triple bond to carbon four, which then has a single bond to a CH two group, which is carbon five, which has a single bond to a CH three group which is carbon six. Note the differing number of hydrogens. When we draw this structure, we then fill in the correct number of hydrogens based on how many bonds our carbon has. So these terminal carbons have three hydrogens, a carbon with no other bonds, but internal is H two. The carbons in the triple bond that are internal, have no hydrogens because they have three bonds in a triple bond and one to the other carbon. And then the carbon with the two chlorine also has no hydrogens because it has four bonds. So if you were drawing this, rather than picking for multiple choice, you'd need to fill in your proper number of hydrogens. But we have our correct answer here. The condensed structural formula of 22 di Chloro three hex line is choice C. See you in the next video.

Draw the condensed structural or line-angle formula if cyclic, for each of the following:
b. 1,1-dibromo-2-pentyne

Key Concepts

Cyclic Structures

Line-Angle Formula

Dibromo-2-pentyne

Watch next