00:01
Let's start by drawing the different resonance structures for each of these molecules.
00:06
So each of these is going to have one different possibility, and that's where we're going to move a lone pair of electrons, or rather a pie bond, to change the location of this positive charge.
00:21
So let's go ahead and draw them for both of these compounds.
00:26
So in a, this is going to result in a double bond over here.
00:31
And a positive charge sitting over here versus in the second case where we're going to have a double bond sitting over here and a positive charge sitting in the middle.
00:47
So now we just need to consider which of these is going to be the better position for a charge to be shared.
00:55
And there's one key difference here.
00:58
So in the first resonant structure, this positive charge, charge is sitting on a primary carbon, carbon with just one other attachment.
01:07
However, on the second resonance structure, this one is still on a primary carbon, but in this case, this is a secondary carbon.
01:17
And this is going to make a big difference.
01:20
So as a result, this here is going to be the better compound.
01:26
So that means that we'll go ahead and say this is going to be more stable due to a secondary carbon.
01:45
That's not two degrees celsius.
01:47
That's a secondary carbon that the charge is on.
01:56
And now we can move on to b.
01:59
I'm going to go ahead and draw the structures for these and i'll be with you in just a moment.
02:05
Okay, so here's our structures.
02:08
The next thing to do is to draw the resonance structures that we can get.
02:13
So in the first one, we're going to have a resonance structure.
02:17
If we kick these electrons up onto the oxygen, because we know that the oxygen currently just has two loan pairs, and it will happily take a third lone pair because of its electrow negativity.
02:30
So that's going to give us a resultant that will look a little bit like this.
02:37
And we do also need to move this.
02:40
Loan pair here as a result of that.
02:43
So that means that this is not going to be a double bond over here, but instead we're going to have a double bond sitting here.
02:53
And let's do the exact same thing for our second compound, the only difference being this double bond here, well, has one extra carbon sitting on the end.
03:09
So this is going to look like this.
03:16
Very, very similar compounds that we're working with here.
03:22
Okay.
03:23
So there we've got our compound and now let's consider which of these is going to be better.
03:30
So in this case, because they're so incredibly similar, what it comes down to is the length of this carbon chain.
03:37
And in this case, the second one is going to be more stable due to a longer carbon chain.
03:53
And that's all there is to it, because in every other manner, they are identical.
04:01
Now, i'm going to go ahead and draw the isomers that we're working with in c, and then i'll be right with you.
04:11
So let's go ahead and draw the resonant structures...