Arrange the following molecules from lowest to highest boiling point. (LO 8.9) (I)

(II)

(III)

(IV)

(a) I 6 II 6 III 6 IV (b) II 6 III 6 I 6 IV (c) IV 6 II 6 III 6 I (d) IV 6 I 6 II 6 III

Video transcript

Hello everyone. So in this video we're trying to do is arrange these following four different compounds from the highest boiling point to the lowest point point. So what we have to do in this case is to take into account our inter molecular forces or I. M. F. Which is that the stronger the I. M. F. The higher the boiling point. But taking a look at molecule or compound A. Here we all have just um hydrocarbons which is just hydrogen carbons. We don't have any other sort of bonds. And we know that hydrocarbons are non polar. So you're going to say to the low note that everything here is containing non polar bonds. And then let's look at B. B. Here we have this auction and because of this we have a slightly polar molecule because the auction is more electro negative compared to carbon or hydrogen. And this kind of put towards the left molecule, we don't really have it in the center here then it does have a whole um dipole moment to the left. So here we can say that we have slightly polar and strong the arrow towards the oxygen because it's responsible by the auction. Now, taking a look at compound C. Here, we can see that everything is the same in regards to our hydrocarbons. Same thing as here. But over to the right side we have a O. H. Group was especially about this group is this is hydrogen bonding. What hydrogen bonding is if you recall we'll do this maybe a different color in green in the center. Well hydrogen bonds with either nitrogen auction or flooring and it creates this really strong bond which we call hydrogen bonding. We see that present here in a molecule C. With O. H. So we have each bonding and we have one source of this. I just put parentheses one take a look at compound D. Now we see an O. H. Group over to the right, just as we did in the molecule C. But we also have another one here. Let's go ahead and circle those One and two and say that we have aged bonding except in parentheses. This time will be too because we have two sources of this actually go ahead and rewrite this number two more clearly. All right. So now that we kind of looked at all four of these different compounds that we can do now is go ahead and rank them by the order and strength of these inter molecular forces. So we can see the strongest one here is going to be compound D. Because we have two sources of hydrogen bonding. So that's going to be D. First that's the one with the highest boiling point. Now next will be the one with just one hydrogen bonding which we determined to be molecule see here. So put C. Next to that then after that we're comparing molecule A. Or compound A. With molecule B. And we said already that we do have a certainly polar molecule here because of this auction. Adam here mean that this does have this disciple disciple and this one just has learned and dispersion because all molecules have London dispersion. So then that makes be our next compound with the highest temperature and will be a last of having the lowest boiling point. So my final answer then is going to be disorder where D. Is the strongest force containing molecule, which means that we also have a higher boiling point and a being the molecule with the weakest inter molecular forces, making it the no. I killed with the lowest boiling point.