Dichloroethylene 1C2H2Cl22 has three forms (isomers), each of which is a different substance. (b) Which of these isomers has a zero dipole moment?

Video transcript

Alright. So here we need to identify the compound below. That does not have a net die po so what does that mean? Does not have a net dipole moment basically. It means that that molecule is non polar. So which one of these is a non polar molecule? That's what we're looking for. Okay, so s. c. l. four. If we draw this out, we're going to have sulfur In the center with the four chlorine. Okay. And sulfur is in group 68 needs six valence electrons. So we have four bonds giving it four valence electrons. So it needs to more that means it's actually going to have a lone pair. So there's a lone pair on the sulfur. So it's sulfur did not have a lone pair and it was just simply surrounded by the same by chlorine. Then we would say yes, this is a non polar molecule because it's completely symmetrical. It's surrounded by the same atoms. But there is a disciple and this is not a perfect shaped molecule. So it's going to be polar. Alright, so, a here um It's not our answer because we're looking for one that does not have a net typo. So a non polar one. So not our answer. All right. S. O. So s So we know it's going to be polar because it's simply just sulfur and oxygen. Right? And oxygen here is more electro negative. So there's going to be a Deibel moment here. So this one is polar. I did not draw this molecule completely, but we don't really need to draw it completely because we just know there's sulfur and oxygen and oxygen is going to have a larger die pool towards that. Right? So we have A L. F. Um three. So if we draw that one out We have aluminum. It is in group 38. So it only needs three valence electrons and it has three florins here. So we can see it. Um aluminum here does not have any lone pairs because it already has um you know the correct number of valence electrons and Florence of course are going to have three lone pairs each just like in the first one chlorine would have three lone pair each doesn't really change our answer. And the polarity we can say that we have a molecule that is surrounded by the same elements with no lone pairs. So this is actually non polar. Alright, so um see here is our answer. Let's go ahead and see if we have another non polar molecule. So we have PCL three. If we draw that we're going to see that we have phosphorus with three chlorine And phosphorus is in group five a. So it needs five valence electrons and we have 123 right now. So we need two more which means it has a lone pair. So just like the first one it has one lone pair which makes it automatically polar. Okay so it's not the answer. And then lastly we have Hbr again there's just going to be hydrogen and bromine bonded together. Hydrogen compared to bromine is way way less electro negative. So there's going to be a large typo arrow or moment pointing towards roaming. So yes, there is going to be a net typo, it is polar and not our answer. So it turns out there's only one non polar molecule and it was um this one right here. So see here is our correct answer. Thank you so much for watching.