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So that's one possible product. The other possibility, instead of having my two hydrogens add as wedges, I can have my two hydrogens add as dashes. So there's a hydrogen, and then here's a dash, and there's a hydrogen. So at this top carbon here, now my ethyl group is coming out at me. And at this bottom carbon, now my... | Hydrogenation Alkenes and Alkynes Organic chemistry Khan Academy.mp3 |
So at this top carbon here, now my ethyl group is coming out at me. And at this bottom carbon, now my methyl group is coming out at me like this. So I have two possibilities. And if I look at these two products, I can see that they are enantiomers. They are mirror images of each other. So these two would be my enantiom... | Hydrogenation Alkenes and Alkynes Organic chemistry Khan Academy.mp3 |
And if I look at these two products, I can see that they are enantiomers. They are mirror images of each other. So these two would be my enantiomers, and these would be the products of my reaction. So be very careful when thinking about syn additions here. Let's do one more example of a hydrogenation reaction. Let's do... | Hydrogenation Alkenes and Alkynes Organic chemistry Khan Academy.mp3 |
So be very careful when thinking about syn additions here. Let's do one more example of a hydrogenation reaction. Let's do a bridged bicyclic compound. So let's look at a famous bridged bicyclic compound. Let's see if we can draw it here. So I'm going to, there's my bridge. And then I'm going to go like this, and then ... | Hydrogenation Alkenes and Alkynes Organic chemistry Khan Academy.mp3 |
So let's look at a famous bridged bicyclic compound. Let's see if we can draw it here. So I'm going to, there's my bridge. And then I'm going to go like this, and then I'm going to draw that back carbon a little bit off like that. And my double bond is going to go right here, and then this is going to be a methyl group... | Hydrogenation Alkenes and Alkynes Organic chemistry Khan Academy.mp3 |
And then I'm going to go like this, and then I'm going to draw that back carbon a little bit off like that. And my double bond is going to go right here, and then this is going to be a methyl group. And then up here are going to be two methyl groups like that. So this is alpha-pining. This is alpha-pining right here, f... | Hydrogenation Alkenes and Alkynes Organic chemistry Khan Academy.mp3 |
So this is alpha-pining. This is alpha-pining right here, found in turpentine. And you can see there's an alkene on this. So if I took this alpha-pining molecule and I wanted to hydrogenate it, so I could use palladium and charcoal, or palladium and carbon. And if I think about what happens in this mechanism, I know th... | Hydrogenation Alkenes and Alkynes Organic chemistry Khan Academy.mp3 |
So if I took this alpha-pining molecule and I wanted to hydrogenate it, so I could use palladium and charcoal, or palladium and carbon. And if I think about what happens in this mechanism, I know that my metal catalyst there, my palladium, is going to be flat like that. And so when it has those hydrogens, when the pall... | Hydrogenation Alkenes and Alkynes Organic chemistry Khan Academy.mp3 |
Think about this guy over here. Think about the alpha-pining as molecules like a spaceship. And the spaceship is approaching the docking station. So the spaceship is slowly going down. The spaceship is going to approach the docking station. And there's only one way the spaceship can approach the docking station. And th... | Hydrogenation Alkenes and Alkynes Organic chemistry Khan Academy.mp3 |
So the spaceship is slowly going down. The spaceship is going to approach the docking station. And there's only one way the spaceship can approach the docking station. And that is the way in which we have drawn it right here. It could not flip upside down and approach it from the top because of the steric hindrance of ... | Hydrogenation Alkenes and Alkynes Organic chemistry Khan Academy.mp3 |
And that is the way in which we have drawn it right here. It could not flip upside down and approach it from the top because of the steric hindrance of these methyl groups. So this is the way that it approaches. In this part of the molecule, your alkene is the flat part. So it's easiest for the molecule to approach in ... | Hydrogenation Alkenes and Alkynes Organic chemistry Khan Academy.mp3 |
In this part of the molecule, your alkene is the flat part. So it's easiest for the molecule to approach in this way. The spaceship analogy always helps my students. So there's only one product for this reaction. And let's see if we can draw it here. So there's one product for this reaction. And let's see what it would... | Hydrogenation Alkenes and Alkynes Organic chemistry Khan Academy.mp3 |
So there's only one product for this reaction. And let's see if we can draw it here. So there's one product for this reaction. And let's see what it would look like. It would look something like this. So we have our two methyl groups right here. So the hydrogens are going to add from below. | Hydrogenation Alkenes and Alkynes Organic chemistry Khan Academy.mp3 |
And let's see what it would look like. It would look something like this. So we have our two methyl groups right here. So the hydrogens are going to add from below. So you can see the hydrogens are going to add from below. So this hydrogen, let's say it adds right here. That's going to push this methyl group up. | Hydrogenation Alkenes and Alkynes Organic chemistry Khan Academy.mp3 |
So the hydrogens are going to add from below. So you can see the hydrogens are going to add from below. So this hydrogen, let's say it adds right here. That's going to push this methyl group up. So it's going to push that methyl group up. So that methyl group gets pushed up when that hydrogen adds right down here. And ... | Hydrogenation Alkenes and Alkynes Organic chemistry Khan Academy.mp3 |
That's going to push this methyl group up. So it's going to push that methyl group up. So that methyl group gets pushed up when that hydrogen adds right down here. And then this other hydrogen is going to add to the opposite side. This other hydrogen is going to add to this one right here. And so we can show the additi... | Hydrogenation Alkenes and Alkynes Organic chemistry Khan Academy.mp3 |
And then this other hydrogen is going to add to the opposite side. This other hydrogen is going to add to this one right here. And so we can show the addition of that hydrogen. So there's my syn addition of these two hydrogens. And there was something else in that carbon. It was another hydrogen. So another hydrogen go... | Hydrogenation Alkenes and Alkynes Organic chemistry Khan Academy.mp3 |
In this video, we're going to talk a little bit about amines. And these are just organic compounds, where you have a nitrogen bonded to groups that contain carbon. So if I were to just draw some amines right here, you could have something like this, where you have a nitrogen bonded to two hydrogens, and then maybe some... | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
Maybe it's just one carbon right here. So maybe you have a carbon which is also bonded to three hydrogens like this. In this case, you would have a primary amine. If you have the nitrogen bonded to two carbons, so if you have something like this, a nitrogen bonded to two carbons, so it has one carbon chain right there.... | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
If you have the nitrogen bonded to two carbons, so if you have something like this, a nitrogen bonded to two carbons, so it has one carbon chain right there. And I'm just drawing methyl groups here, because the chain could just keep on going. Maybe you have two like that, and then you have a hydrogen right there. This ... | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
This would be a secondary amine. And then finally, you could imagine if you had it bonded to three, it would be a tertiary amine. This is just to get you introduced to the terminology. Just like that. Now, like all of the other new groups or new types of compounds that we've explored, what I want to do is just introduc... | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
Just like that. Now, like all of the other new groups or new types of compounds that we've explored, what I want to do is just introduce you to the naming of it. Because one, that lets you recognize them when you hear their names, but it also, I think, on some level, familiarizes you with your structure. So let's do a ... | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
So let's do a couple of naming examples. I drew these ahead of time. And in general, just to remember, amines are pretty high priority group. Out of all of the things that we've learned so far, the only thing that is a higher priority is actually the alcohols, or actually the thiols, which I don't even remember if I di... | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
Out of all of the things that we've learned so far, the only thing that is a higher priority is actually the alcohols, or actually the thiols, which I don't even remember if I did a video on it. But thiols are just like alcohols, but instead of an oxygen, you have a sulfur. So this comes right after those. So let's thi... | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
So let's think about this one right here. So we always want to look for our longest carbon chain. Our longest carbon chain is right here. 1, 2, 3, 4, 5, 6, 7 carbons. You want to start numbering it closer to the functional group. 1, 2, 3, 4, 5, 6, and 7. And then the functional group is on the 2 carbon right there. | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
1, 2, 3, 4, 5, 6, 7 carbons. You want to start numbering it closer to the functional group. 1, 2, 3, 4, 5, 6, and 7. And then the functional group is on the 2 carbon right there. So first of all, 7 carbons, we would use the prefix hept. So it would be heptan. Let me write that down. | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
And then the functional group is on the 2 carbon right there. So first of all, 7 carbons, we would use the prefix hept. So it would be heptan. Let me write that down. So it would be heptan. And since our functional group is an amine in this situation, it has a higher priority than the fact that this is an alkane, so th... | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
Let me write that down. So it would be heptan. And since our functional group is an amine in this situation, it has a higher priority than the fact that this is an alkane, so this will actually define the suffix. So we would then say, well, then on the 2 carbon right over here, we have the amine group. So it's heptan-2... | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
So we would then say, well, then on the 2 carbon right over here, we have the amine group. So it's heptan-2-amine. And we're done. We know that we have an amine group on the 2 carbon. Now let's do this one. This one's a little bit more hairy. So first of all, we always want to figure out the longest carbon chain. | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
We know that we have an amine group on the 2 carbon. Now let's do this one. This one's a little bit more hairy. So first of all, we always want to figure out the longest carbon chain. And it looks like the ring is going to be the longest carbon chain. We have 1, 2, 3, 4, 5, 6 carbons. So this thing right here is the lo... | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
So first of all, we always want to figure out the longest carbon chain. And it looks like the ring is going to be the longest carbon chain. We have 1, 2, 3, 4, 5, 6 carbons. So this thing right here is the longest chain. We only have 1, 2 carbons right there, 1 carbon, 1 carbon right over there. So our root is going to... | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
So this thing right here is the longest chain. We only have 1, 2 carbons right there, 1 carbon, 1 carbon right over there. So our root is going to be cyclohexane. I want to make sure I have enough space. Cyclohexane. And then once again, it's an amine. So this is going to take higher priority. | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
I want to make sure I have enough space. Cyclohexane. And then once again, it's an amine. So this is going to take higher priority. So we're not just going to put an e at the end and call this cyclohexane. This takes higher priority. So it'll actually define the suffix. | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
So this is going to take higher priority. So we're not just going to put an e at the end and call this cyclohexane. This takes higher priority. So it'll actually define the suffix. And another thing to think about is you could say, OK, this is going to be the 1 carbon. And so you could call this cyclohexane 1 amine. Bu... | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
So it'll actually define the suffix. And another thing to think about is you could say, OK, this is going to be the 1 carbon. And so you could call this cyclohexane 1 amine. But in general, if this is defining it, you always assume that you're going to start numbering right there at number 1. So you could just call thi... | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
But in general, if this is defining it, you always assume that you're going to start numbering right there at number 1. So you could just call this cyclohexane amine. If it's written like this, you assume that the 1 carbon is where the amine group is attached. Now what else do we have on this thing? We took care of the... | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
Now what else do we have on this thing? We took care of the amine. We took care of the cycle. Well, we have this ether right here. And this ether has 1, 2 carbons. If it was just a 2 carbon chain, it would be ethane. But since we have an ether, it's bonded to this oxygen, we call this ethoxy. | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
Well, we have this ether right here. And this ether has 1, 2 carbons. If it was just a 2 carbon chain, it would be ethane. But since we have an ether, it's bonded to this oxygen, we call this ethoxy. So that right there is ethoxy. And we're going to have to think about how we're going to number this. So I'll leave that... | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
But since we have an ether, it's bonded to this oxygen, we call this ethoxy. So that right there is ethoxy. And we're going to have to think about how we're going to number this. So I'll leave that alone. And what are these over here? Well, this is a methyl group. That's a CH3 implicitly. | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
So I'll leave that alone. And what are these over here? Well, this is a methyl group. That's a CH3 implicitly. You don't see it drawn. There's a carbon there. And if carbon is neutral, it has to have 4 bonds. | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
That's a CH3 implicitly. You don't see it drawn. There's a carbon there. And if carbon is neutral, it has to have 4 bonds. And if you only draw 1 of them, the other 3 are assumed to be the hydrogen. So this is a methyl group. And then this is also a methyl group. | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
And if carbon is neutral, it has to have 4 bonds. And if you only draw 1 of them, the other 3 are assumed to be the hydrogen. So this is a methyl group. And then this is also a methyl group. So we have dimethyl. So this is also a methyl group right over there. And when we think about numbering, we could number from 1, ... | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
And then this is also a methyl group. So we have dimethyl. So this is also a methyl group right over there. And when we think about numbering, we could number from 1, 2, 3, or we could start numbering 1, 2, 3. And in general, you want to go numbering in the direction where you hit the functional group first. So we want... | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
And when we think about numbering, we could number from 1, 2, 3, or we could start numbering 1, 2, 3. And in general, you want to go numbering in the direction where you hit the functional group first. So we want to go 1, 2, 3, 4, and 5. So this right here is 5-ethoxy. This is 5-ethoxy. And then this is 1, 2-dimethyl. ... | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
So this right here is 5-ethoxy. This is 5-ethoxy. And then this is 1, 2-dimethyl. These two combined, you would call this 1, 2-dimethyl. And then when you want to list them in order, the ethoxy would take precedence in alphabetical, because the di you shouldn't count in the alphabetical order. This is just saying 2-met... | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
These two combined, you would call this 1, 2-dimethyl. And then when you want to list them in order, the ethoxy would take precedence in alphabetical, because the di you shouldn't count in the alphabetical order. This is just saying 2-methyl. So you really just want to look at the 2 of whatever you're talking about. M ... | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
So you really just want to look at the 2 of whatever you're talking about. M comes after E in alphabetical order. So this is going to be 5-ethoxy. Actually, let me just rewrite the whole thing. So this is going to be 5-ethoxy. 1, 2-dimethyl cyclohexanamine. And we're done. | Amine naming introduction Amines Organic chemistry Khan Academy.mp3 |
Let's compare the structures of ethane and ethene. Ethane is an alkane with an A-N-E ending, and it has the molecular formula C2H6. Ethene is an alkene with an E-N-E ending, and it has the molecular formula C2H4. For two carbons, six hydrogens is the maximum number that you can have, so we say that ethane is completely... | Structure and classification of alkenes.mp3 |
For two carbons, six hydrogens is the maximum number that you can have, so we say that ethane is completely saturated with hydrogens. If we look at ethene, we only have four hydrogens for two carbons, so we say that ethene is unsaturated. So for two carbons, it's possible to have more, so this is unsaturated. Next, let... | Structure and classification of alkenes.mp3 |
Next, let's look at the carbons present in both molecules, and we'll start with ethane. This carbon is sp3 hybridized, and so is this one. So ethane contains two sp3 hybridized carbons, and we know the geometry around an sp3 hybridized carbon is tetrahedral, so we should have tetrahedral geometry around both of these c... | Structure and classification of alkenes.mp3 |
For ethene, let me use a different color here. So this carbon and this carbon are both sp2 hybridized, so sp2 hybridized carbons, and we know the geometry around an sp2 hybridized carbon is trigonal planar, so there's planar geometry around both of these carbons. Finally, let's look at the bonding between the two carbo... | Structure and classification of alkenes.mp3 |
So for ethane, this sigma bond between the two carbons has some free rotation, so different conformations of the ethane molecule are possible, so we have free rotation, free rotation about the sigma bond between our two carbon atoms. But for ethene, if we look at those two carbon atoms, so this one and this one, there'... | Structure and classification of alkenes.mp3 |
For ethene or ethylene, our two sp2 hybridized carbons have planar geometry around them, so if I rotate this molecule to the side here, you can see that it is planar, and there's no free rotation because of this double bond, because of the presence of a pi bond, so here I am trying to rotate the model set, and you can ... | Structure and classification of alkenes.mp3 |
We have an alkyl group coming off of this carbon, a methyl group, and so this is an example of a monosubstituted alkene. If I want to name this alkene, we saw how to name them in an earlier video. We would make this carbon one, this is carbon two, and this is carbon three, so longest carbon chain, including our alkene,... | Structure and classification of alkenes.mp3 |
Next, let's look at a disubstituted alkene, so now we're talking about two R groups, so here I've put in R and R prime, and R and R prime might be the same or they might be different. Here, R and R prime are on the same carbon, but it's possible to have a disubstituted alkene where R and R prime are bonded to different... | Structure and classification of alkenes.mp3 |
Let's look at this one down here and let's name it, so find our longest carbon chain that includes our double bond, and I wanna give the lowest number possible to our double bond, so we're gonna start right here at carbon one, and this is carbon two, and this is carbon three, so three-carbon alkene is called propene, a... | Structure and classification of alkenes.mp3 |
So this is, let's see, we have a methyl group on the number two carbon, it is a pentene, and that's double bond between the number two and number three carbons. So this is two methyl, two methyl pent, pent-2-ene, pent-2-ene. So that's what we start with, we're in the presence, we're in a acidic environment, we've got, ... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
Well, the double bond is now gone, the number three carbon gains this hydrogen, and now the number two carbon gains a hydroxyl group. So one way to think about this is, in the presence of an acid, it's acid catalyzed, we have gained two hydrogens and an oxygen, which is, well, we've gained the built, what could be used... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
So let's think about how this actually happens in the presence of our hydronium. So let me redraw this molecule right over here. So let me copy and paste it. So, and that's not exactly it yet, that is just with the single bond. So let me draw, whoops, wrong tool. Let me draw the double bond there. And now let me put it... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
So, and that's not exactly it yet, that is just with the single bond. So let me draw, whoops, wrong tool. Let me draw the double bond there. And now let me put it in the presence of some hydronium. All right, so we have an oxygen bonded to, so this would just be water, as oxygen has two lone pairs, but hydronium's a si... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
And now let me put it in the presence of some hydronium. All right, so we have an oxygen bonded to, so this would just be water, as oxygen has two lone pairs, but hydronium's a situation where oxygen is sharing one of those lone pairs with a hydrogen proton, thus making the entire molecule positive, because you could d... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
And this can be pretty reactive, because we know that oxygen is quite electronegative, it likes to keep its electrons. So what if there was a way, what if there was a way for the oxygen to take back the electrons in this bond right over here, the two electrons in this bond? Well, what if one of these carbons, especiall... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
And you might say, well, that's reasonable, but which of these carbons would actually do it? And to think about which of those carbons would do it, we have to turn to Markovnikov's rule. Markovnikov's rule tells us that, look, if you have a reaction like this, an alkene reaction, the carbon that's already attached to m... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
The carbon that's attached to more functional groups is more likely to gain more functional groups. Another way to think about it is think about, well, what is the order of the carbons? Because the higher order of the carbon, the more stable it will be if it forms some type of cation. So if you look at this carbon righ... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
So if you look at this carbon right over here, our number two carbon, let me circle it, our number two carbon is bonded to one, two, three carbons. So this is a tertiary carbon. This one right over here, this carbon, the other side of the double bond, is only bonded to one, two carbons. So this is a secondary carbon. S... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
So this is a secondary carbon. So the tertiary carbon is going to be more stable as a carbocation. You can think of it as it can spread the charge a little bit so it would be more likely to lose the electrons in one of these bonds. And so the way that we could think about this mechanism, and it might be a little bit cl... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
And so the way that we could think about this mechanism, and it might be a little bit clearer when we form the carbocation, is let's have, I'll do this in blue, let's have these two electrons that form this bond. Well now, they form a bond with that hydrogen and now the oxygen can take back these two electrons and what... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
Remember, all of these things are going back and forth depending on how things bump into each other. But what are we left with? So let me copy and paste this again. And I'm copying and pasting it away just so I kind of, you can view this as a backbone and I'll add what I need to add. So once this happens, we have this ... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
And I'm copying and pasting it away just so I kind of, you can view this as a backbone and I'll add what I need to add. So once this happens, we have this carbon, the number three carbon, now, whoops, I keep using the wrong tool. The number three carbon now forms a bond with this hydrogen, just like that. This carbon, ... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
This carbon, our number two carbon, has lost an electron. It's no longer sharing this bond. And so now, it is going to have a positive charge. It is a carbocation and once again, it is a tertiary carbocation. It is bounded to one, two, three carbons. That is stable, more stable than if we did it the other way around. I... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
It is a carbocation and once again, it is a tertiary carbocation. It is bounded to one, two, three carbons. That is stable, more stable than if we did it the other way around. If this one grabbed the hydrogen somehow, then this would be a secondary carbocation. It'd be harder for it to spread that positive charge aroun... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
If this one grabbed the hydrogen somehow, then this would be a secondary carbocation. It'd be harder for it to spread that positive charge around. And what about our molecule up here? Well, let's see what it looks like now. We have our oxygen bonded to the two hydrogens. It had one of those lone pairs and now, the elec... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
Well, let's see what it looks like now. We have our oxygen bonded to the two hydrogens. It had one of those lone pairs and now, the electrons in this bond are now going to form another lone pair. So it took back an electron. Or you could think of it, it gave away a hydrogen proton. And so this is now just neutral water... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
So it took back an electron. Or you could think of it, it gave away a hydrogen proton. And so this is now just neutral water and we see that we have a conservation of charge here. This was positively charged. Now, our original molecule is positively charged. And what feels good about this is we're getting close to our ... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
This was positively charged. Now, our original molecule is positively charged. And what feels good about this is we're getting close to our end product, at least on our number three carbon. We now have this hydrogen. Now, we need to think about, well, how do we get a hydroxyl group added right over here? Well, we have ... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
We now have this hydrogen. Now, we need to think about, well, how do we get a hydroxyl group added right over here? Well, we have all this water floating around. I could use this water molecule but the odds of it being the exact same water molecule, we don't know. But there's all sorts of water molecules. We're in an a... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
I could use this water molecule but the odds of it being the exact same water molecule, we don't know. But there's all sorts of water molecules. We're in an aqueous solution. So let me draw another water molecule here. So the water molecules are all equivalent but let me draw another water molecule here. And you can im... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
So let me draw another water molecule here. So the water molecules are all equivalent but let me draw another water molecule here. And you can imagine, if they just bump into each other in just the right way, this is, water is a polar molecule. It has a partially negative end near the oxygen because the oxygen likes to... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
It has a partially negative end near the oxygen because the oxygen likes to hog the electrons. And then you have a partial positive end near the hydrogens because they get their electrons hogged. So you can imagine the oxygen end might be attracted to this tertiary carbocation. And so just bumping in in just the right ... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
And so just bumping in in just the right way, it might form a bond. So let me, let's say these two electrons right over here, let's say they form a bond with this, with that number two carbon. And then what is going to result? So let me draw, so what is, what is going to result? Let me scroll down a little bit and let ... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
So let me draw, so what is, what is going to result? Let me scroll down a little bit and let me copy and paste, whoops, let me copy and paste our original molecule again. So there we go. So what could happen? So let me construct it actually. So we have the hydrogen there. We have the hydrogen. | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
So what could happen? So let me construct it actually. So we have the hydrogen there. We have the hydrogen. Now this character, so we have the water molecule. So oxygen bonded to two hydrogens. You have this one lone pair that isn't reacting, but then you have the lone pair that does do the reacting. | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
We have the hydrogen. Now this character, so we have the water molecule. So oxygen bonded to two hydrogens. You have this one lone pair that isn't reacting, but then you have the lone pair that does do the reacting. And so it now forms a bond. Whoops, let me do it in that orange color. It now, it now forms an actual bo... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
You have this one lone pair that isn't reacting, but then you have the lone pair that does do the reacting. And so it now forms a bond. Whoops, let me do it in that orange color. It now, it now forms an actual bond. And we're really close to our final product. We have our hydrogen on the number three carbon. We have mo... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
It now, it now forms an actual bond. And we're really close to our final product. We have our hydrogen on the number three carbon. We have more than we want on our number two carbon. We just want a hydroxyl group. Now we have a whole water bonded to the number two carbon. So somehow we have to get one of these other hy... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
We have more than we want on our number two carbon. We just want a hydroxyl group. Now we have a whole water bonded to the number two carbon. So somehow we have to get one of these other hydrogens swiped off of it. Well, that could happen with just another water molecule. So let's draw that. So another water molecule s... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
So somehow we have to get one of these other hydrogens swiped off of it. Well, that could happen with just another water molecule. So let's draw that. So another water molecule someplace. I'll do it in a different color just to differentiate. Although as we know, water, well it's hard to say even what color is water if... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
So another water molecule someplace. I'll do it in a different color just to differentiate. Although as we know, water, well it's hard to say even what color is water if you're looking at the molecular scale. So here we go. We're really in the home stretch at this point. You have another water molecule. Let's say, let ... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
So here we go. We're really in the home stretch at this point. You have another water molecule. Let's say, let me pick a color. So let's say these electrons right over here. Maybe they form a bond with that hydrogen proton. And then these, the electrons in that bond can go back to form a lone pair on that oxygen. | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
Let's say, let me pick a color. So let's say these electrons right over here. Maybe they form a bond with that hydrogen proton. And then these, the electrons in that bond can go back to form a lone pair on that oxygen. And then what are we left with? And this really is the home stretch. So we are in equilibrium with, s... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
And then these, the electrons in that bond can go back to form a lone pair on that oxygen. And then what are we left with? And this really is the home stretch. So we are in equilibrium with, so let me draw my five carbons. So let's see, I have H3C, carbon, carbon, CH2, CH3. I have a CH3. I say H3C instead of CH3. | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
So we are in equilibrium with, so let me draw my five carbons. So let's see, I have H3C, carbon, carbon, CH2, CH3. I have a CH3. I say H3C instead of CH3. I wrote it that way just so it's clear that the carbons are bonded to the carbons. You have the original hydrogen right over there. You have the one that we just add... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
I say H3C instead of CH3. I wrote it that way just so it's clear that the carbons are bonded to the carbons. You have the original hydrogen right over there. You have the one that we just added as part of this mechanism. You have this orange bond to now this hydroxyl group, the hydroxyl group. And it had one lone pair ... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
You have the one that we just added as part of this mechanism. You have this orange bond to now this hydroxyl group, the hydroxyl group. And it had one lone pair before. It had one lone pair before, but now it took both of the electrons from this bond to form another lone pair, to form another lone pair, which I am dep... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
It had one lone pair before, but now it took both of the electrons from this bond to form another lone pair, to form another lone pair, which I am depicting in pink. And then this water is now, or this water molecule is now a hydronium molecule. So let's draw that. So this is now oxygen, hydrogen, hydrogen. Had one lon... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
So this is now oxygen, hydrogen, hydrogen. Had one lone pair that didn't react, but it had one lone pair that I put in blue that is reacting with this hydrogen proton, with that hydrogen, just like this. And so since it got the hydrogen proton, it's giving its, or sharing its electrons now, now this has a positive, thi... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
Oh, I have to be very careful. In the last step, I forgot to draw the positive charge. You always wanna make sure that your charge is being conserved. We started off with a positive charge on the hydronium. Then we have the positive charge on a tertiary carbocation right over here on a number two carbon. And now we hav... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
We started off with a positive charge on the hydronium. Then we have the positive charge on a tertiary carbocation right over here on a number two carbon. And now we have the positive charge would be right over here, because that oxygen, what we saw before, that oxygen, which this water molecule was neutral, but you co... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
So you could view it as maybe it's giving it away an electron. And so now it becomes positive. And then, and then the positive charge finally gets transferred to that other water molecule when it becomes hydronium. But just like that, we are done. We have added a hydroxyl group and a hydrogen combined. That's a water, ... | Addition of water (acid-catalyzed) mechanism Organic chemistry Khan Academy.mp3 |
So according to Markovnikov's rules, let's go ahead and write that down here. So you have to think about Markovnikov when you're doing this reaction. And this is an acid catalyzed reaction. So technically this reaction is at equilibrium and we will cover that at the very end of the video here. So let's look at the mech... | Hydration Alkenes and Alkynes Organic chemistry Khan Academy.mp3 |
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