(a) Consider the following two molecules: PCl3 and BCl3. Which molecule has a nonzero dipole moment?

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Alrighty here. So we have to draw a loose structure of three possible ice smurfs of di Bruno dressing. So we have C two H two, B R two. So we're basically saying there's three different compounds with the same formula but different atom connectivity. Okay, so note one of the ISIS members in particular has no disciple moment, meaning that it is going to be non polar by the other due to so we have one non polar and then two polar molecules. So let's go ahead and draw them. So we're going to go ahead and do the non polar first. So here we're going to have carbons as the central atoms. Uh they're both going to be central atoms, they're going to be connected to one another and then we have two hydrogen is and to morrow means alright, so in order to make this first one non polar, obviously we do know that the the bonds between carbon and bromine are going to be polar, right? Because roaming is very electro negative. But somehow those disciple moments are going to cancel one another out and make it overall a non polar molecule. Overall there's going to be a zero net dipole moment. And the only way that's going to be possible is if we have bruning two of the bruning bonds um opposite one another. Sorry, I forgot the work. So opposite one another and then of course the other hydrogen will just be opposite one another as well. But it doesn't really matter for the hydrogen because hydrogen are not very electro negative. So we are going to have a disciple moment going from carbon to brahman because brahman is very electro negative but we're also going to have one going over here and it's just like there's this symmetry here going on and these two actually going to cancel each other out and this overall will be in on the polar molecule. Okay, So then the other two are going to be polar. Let's go ahead and draw the other one. Okay, I'm sorry, I did forget a double bond between carbon. We do know that carbon of course needs four bonds usually if it can make it and here they are double bonding to one another. Alright, so the second one is going to be I mean they're going to be very similar. We're just going to be kind of shuffling the brahmins and the hydrogen is here. But the double bond between carbon is going to stay there. All right. So for non polar, we just need to make sure that we don't have bro means opposite one another. So that they actually don't cancel out. So we're going to put to borrow means right here And then the two hydrogen is over here. Right? So, again, we're going to have a diaper moment going this way. Diaper moment going that way and then basically overall there is going to be a nets type of moment between the two bromance. Right? So this is actually going to make it polar. So this is going to be polar because they're not opposite one another. And then we have a third eye summer. Again, we're going to move one of these bro means to the other side. Of course we're going to move this one not down here, but up here to the left. Ok, So again, carbon double bonded to one another. And then we're going to have the two bombings on the same side of the double bond, But not opposite one another. So in the in the second one, in the polar one, we had to borrow means opposite or on the opposite side of the double bond, not opposite one another. And then here again, this is going to be polar. We have the tube remains on the same side of the double bond, but still not opposite one another. And there's still going to be a net dipole moment going this way now. There we go. So those are the three ISIS members of WMO definition of this molecule right here. If you have any questions, please let us know. And we'll see you in the next video

(a) Consider the following two molecules: PCl3 and BCl3. Which molecule has a nonzero dipole moment?

Verified Solution

Key Concepts

Molecular Geometry

Dipole Moment

Polarity of Molecules