CHM 121 LECTURE - MONDAY

[00:00:31]Good morning. Um, I hear you in the background, so I know you can hear me.

[00:00:42]In the last class, I asked you to look at a couple of things.

[00:00:49]I do not know if you did. Do we have any questions?

[00:00:53]Can we start from there? Any questions?

[00:00:56]Either you write it in the Q&A.

[00:01:00]Good morning, K. I guess you can hear me.

[00:01:05]questions please put in the Q&A section or you raise your hand now so that uh we can take that's those of you who who had a chance to look at uh I don't see any hand up I don't see any question in Q&A So I will just quickly revise it because I don't trust you people. You probably were busy eating rice and beans.

[00:01:46]So we've been talking about carboniles.

[00:01:51]We looked at the two types alihides and ketones.

[00:01:56]looked at how to name them, their oxidation and reduction reactions. Looked at their physical properties, how alihides are more polar.

[00:02:12]Then looked at reactions that they mostly will undergo nucleophilic addition reactions.

[00:02:22]And then looked at how to differentiate how the highs from ketones, the kind of reaction undergo and I think okay we looked at condensation reactions with ammonia where they formed all kinds of immune compounds and then I think We stopped at some of the tests. Yes, I told you to look this up. Silver mirror test. Uh so the felings test, you're going to if you haven't come across it already, you're going to come across it in the lab. This is basically a test named after the scientists that discovered it.

[00:03:15]It's used to differentiate alihides from ketones.

[00:03:20]You also come across it when you're talking about sugars. because it can also differentiate reducing sugars.

[00:03:28]Basically, it's an oxidation reaction.

[00:03:31]You have what you call the felling solution A and felling solution B.

[00:03:37]You will add them together and then the chemistry behind it is that okay selling solution A contains copper sulfate okay copper sulfate is blue in water copper sulfate hydrates it has a water of hydration I think five mole It was either five or six can't remember that but the compound is blue.

[00:04:12]So when you mix it with the felling solution B which contains a mixture of sodium hydroxide and sodium potassium tates uh titaric acid is 23 dihydroxy butane diioic acid.

[00:04:39]Uh 1 2 3 4. This is a very easy way to draw it. O H here. O H here. Oh no, wait.

[00:04:50]I've drawn more I've drawn more I've drawn more carbonized than I needed.

[00:05:06]Uh yeah, let me do this.

[00:05:11]Anyway, you you will get this you will get this one online when you go and check cuz I've already sent you there.

[00:05:20]1 2 3 4 and then you have O here, O H here, O H here.

[00:05:36]Okay, I'm drawing this for you in case those of you who are who haven't bothered to learn nomenclature. So this is carbon one, carbon 2 here, carbon 3 here, carbon four here. That's why it's butane diic. We're going to start acid so that some of you will see but that's again why I'm focusing on this. Okay. Butane diic see it has two carboniles and they're terminal.

[00:06:09]Okay. Then dihydroxy 2 three. They're on carbon 2 and three.

[00:06:16]The common name is tataric acid. We're going to look at them when we talk about dicaroxilic acids when we start talking about caroxilic acids. But here it's just a solution as part of the fing solution.

[00:06:31]Okay. So because it's an oxidation reaction and you know if you think back to when we dealt with oxidation of carbon you see that it's only alihide that can be oxidized. When you oxidize ketones, they usually will break up into two compound giving you two acids. Okay? But when you oxidize alihides to give you one acid. But the benefit of this test is mainly in the color change and that color change is due to the copper that changes from copper 2 to copper one. So copper 2 in copper sulfate is blue but copper one in copper oxide is brownish.

[00:07:21]So if you take that [clears throat] felling solution A and B you mix it and then you put alihide and ketone into the solution or you put alihide in one solution ketone in another solution.

[00:07:33]The solution that has alihide, you will see a color change there because the alihide will convert the copper 2 in copper 2 sulfate in the fing solution to copper one as copper oxide while the ketone cannot do that.

[00:07:52]So because ketone cannot do that if you look at the solution where it is in there will be no color change it will remain blue. That is why this is used as a test to distinguish between alihides and ketones. And when you come across it in the lab, you see that is a test that you're doing. When you're given unknown compounds, you'll be asked to find out whether the unknown compound is an alihide or ketone.

[00:08:18]And down here you can see the equation that is involved.

[00:08:25]And like I said, this is the crucial part. This is your alihide.

[00:08:30]Okay, it's going to become a sodium caroxyicate.

[00:08:36]You will learn about that when we talk about caroxilic acids. But that's what is going to form. And it's an oxidation reaction. If you pay attention, you will see that oxygen has been added. Okay.

[00:08:47]But the crucial thing here is that this car uh copper 2 which was blue as a hydrate of copper sulfate is now reduced.

[00:09:07]we did elect you can know reduction and oxidation based on uh oxidation state or number of electrons. So if you check this has moved from +2 to + one that is a reduction in oxidation number if you still remember those things. So now this copper 2 oxide is brownish.

[00:09:34]So that's basically the utility in this test.

[00:09:39]Okay.

[00:09:41]Um the next one quickly is okay. This explains the failing. So if you looked [clears throat] at it, you would have seen what we're talking about there.

[00:09:54]Carbon can be reduced to alcohols. We saw when we dealing with alcohols that alcohols can be oxidized to carbon. The opposite of oxidation is reduction.

[00:10:04]Okay. So if you can oxidize alcohols to carboniles, primary alcohol to alihide, secondary alcohol to ketones, then the converse is also the case. So you can reduce aldihides to primary alcohols, reduce ketones to secondary alcohols.

[00:10:25]Okay? So that's basically what you see here. And then you can see the examples.

[00:10:30]There are two main ways you can do the reduction.

[00:10:34]Either you're using catalytic hydrogenation where you use a catalyst in the presence of hydrogen. Some of the catalysts include platinum, paladium, nickel.

[00:10:46]Okay, here now is nickel that is shown for the conversion of butanyl to butanol as an alihide to an alcohol. Can see is a primary alcohol. The second one also you see that these are some of the kind of things you can expect in an exam where the where the examiner tries to deceive you. You see here now there is a carbonarbon double bond. Okay. So if you're not paying attention you you'll be concentrating on that. But what you should be concentrating on is the functional group here the alihide.

[00:11:28]Okay. If you look at it and you discover that is the alihide then you know that when you reduce it you're going to get a primary alcohol.

[00:11:37]You can see that that carbon that is connected to the O there has two hydrogen atoms or one carbon atom connected to it. So those are the ways you know a primary alcohol. We've already stated that before. And then in this case you can see that lithium aluminium hydide is the reducing agent. You can also use lithium I mean sodium boro hydide. Sodium borohydide is a milder reducing agent compared to lithium aluminium hydide.

[00:12:15]Okay, you are going to learn more about those if you take chemistry in 200 level which I'm sure some of you will. Okay.

[00:12:28]So that's for reduction of alcohols.

[00:12:32]Okay.

[00:12:34]I mean yeah reduction to alcohols not of. Okay.

[00:12:43]Now this goes to a question someone asked I think two or three classes ago.

[00:12:48]So wherever you are pay attention because I sense that there might be some confusion. So here we just talked about reducing carboniles to alcohols.

[00:13:02]That's the onestep reduction if you like. But you can also reduce carboniles to alkanes.

[00:13:11]Okay? Just like you saw that we can reduce alcohols to alanes. You saw that.

[00:13:16]Okay? But here reducing carbon either ketones or alihides to alkanes that's hydrocarbons. So you're removing the oxygen in carbonide totally.

[00:13:31]Okay. So a simple way of putting it is that the carbonile the CO double bond is removed and replaced with a CH2.

[00:13:40]Okay.

[00:13:41]So when you replace the C HO of alihide with a CH2, you now have a CH3. And when you replace the CO of ketone, you have a CH2. So that's another easy way of looking at it. Okay?

[00:13:57]And there are two main ways you can do this named after the scientists that discovered it. The first one is the Clemenson reduction. The other one that we'll see shortly is the Wolf Kishna.

[00:14:08]Okay. The clemencins reduction uses amalagamated zinc. Amalagamated zinc is zinc with mercury and HCl. So that whole combination is referred to as the Clemenson's reduction. And another thing you should take from this is apart from the fact that it reduces carboniles to hydrocarbons or arenes, it also does it for base sensitive compounds.

[00:14:47]Okay. So that means that because as you see the witcher is basic in nature. So if you're reducing a compound that cannot tolerate a base then it's cleans you will use because if you use a base if you use wishna the reaction will not occur because the basic nature will destroy what you're trying to react.

[00:15:16]Okay. So here you see this is a benzaldihide.

[00:15:23]Okay. And the 4 H is used to represent the hydrogen that the Clemenson's reagent is going to generate.

[00:15:33]Okay. So if it generates four hydrogen, you see that it converts the CHO which is the alihide to CH3.

[00:15:46]And if you look at it critically, what it has added is CH2.

[00:15:52]Okay, cuz there's already one H here.

[00:15:54]So, it has CH2 removes.

[00:15:58]Sorry, it has not CH2 in this case. I think it's easier to say adds two hydrogen atoms.

[00:16:08]Okay, I think that's an easier way because another thing you will notice that no extra carbon is formed is the carbon forming the carbonile that also becomes that. Okay. So this balances this equation. You can see that water is given off.

[00:16:32]So you can call this a condensation reaction. If you call it a condensation reaction, you will not be wrong.

[00:16:40]Okay? But it's Clemenson's reduction because it reduces the carbon.

[00:16:47]Ketones will also undergo that reaction.

[00:16:50]Okay? This is the second one. The wolf kit.

[00:16:54]Okay. Here he uses hydroine.

[00:16:58]Hydroine. We came across that when we're dealing with uh condensation reactions with ammonia.

[00:17:04]Hydroine is an amine. So it's a derivative of ammonia because if you you can use R to represent the NH2. Then you now have R NH2. This is an amine. We're going to look at those groups of compounds later.

[00:17:25]Okay. But here in Wolf Kishna you use hydroine. the presence of a strong base.

[00:17:34]Base can be potassium hydroxide or potassium bioxide.

[00:17:40]Either of them will give you a hydrocarbon.

[00:17:46]Okay? So note the differences and that wisher is for acid sensitive compounds. Okay?

[00:17:54]Again, if you have an alihide or ketone that sensitive to acid, then you'll be using Wolf Krishna if you want to reduce it to an alanine.

[00:18:10]Um, carbonides can also react with alcohols.

[00:18:15]Okay, when alihides react with alcohols, they will form acetiles.

[00:18:21]That's an acetile there.

[00:18:24]form first in the first step one molecule of alcohol will give you a hemi acetile.

[00:18:30]See the structure there. Then a second molecule will give you an acetile. The same thing with ketones. This happens with alihides. The same thing with ketones.

[00:18:41]Will give you hemi and keile.

[00:18:44]Okay? So those are the things you're supposed to have looked at on your own.

[00:18:50]You didn't look at it. I've come and I've shown you again. No. So if you see it in test or exam, don't say your lecturer was wicked and you only getting this because you are year one students. So we don't want to rush you into so that you don't feel you don't feel too bad.

[00:19:16]You're in a university now supposed to be independent.

[00:19:20]Okay. So that has taken almost 30 minutes of our time of something that we're supposed to do with another thing.

[00:19:29]Uh I'm not going to the chat section since you guys don't hear. Let me see.

[00:19:33]Is there any any question in Q&A? No question in Q&A.

[00:19:39]So today's topic want to talk about caroxyic acids.

[00:19:46]can also describe caroxilic acids as carboniles that have the hydroxy group or the O.

[00:19:55]The O is a hydroxy group. Okay. Another way of describing it, you can say if you remember when we are describing uh alihides and ketones, we said that an alihide will have H here. A ketone we have R prime which can be an alile or a group. Now for caroxilic acids you have O there.

[00:20:23]That's probably a good way for you to remember it. Okay. So you can call caroxilic acids carbon that have O or you can call call them caroxil groups.

[00:20:40]So carbon functionality with the hydroxy functionality is called caroxil. You see the spellings subsequently if my pronunciation is giving you issues.

[00:20:55]Okay. So all these different names is up to you which whichever one suits you to use and remember.

[00:21:04]Okay. So that you will know what we're talking about. Okay. Okay. So those first two bullet points talk about what I've just talked about. You can see. So sometimes you can also see it written like this.

[00:21:18]We write alcohol as RH.

[00:21:22]We write alihide as R CO.

[00:21:29]We write ketone as RC R prime. Now you can see caroxilic acid we write as R or sometimes you can see it as R O2 H.

[00:21:44]There are all different ways of abbreviating this compounds that I've just just to remind you there. Okay. You can also have compounds that have more than one caroxyic acid. Okay. We look we saw tataric acid a while ago that had two caroxilic acids in the structure. You will call that a daroxilic acid. If he has three it will be try. If he has many it will be polycaroxilic acid and so on and so forth.

[00:22:19]And then um you're not going to deal with that here. Maybe in your second year you come across fatty acids. You've been hearing about fats and oil. Fats and oil. Fat is solid at room temperature. Oil is liquid at room temperature. Fats and oil are made up of fatty acids.

[00:22:40]Just like proteins are made up of amino acids and carbohydrates are made up of sugars, fats and oil or lipids as some of you might have heard them are made up of fatty acids. Now fatty acids are caroxyic acids with long alifhatic chains.

[00:23:01]Okay, like I said as you go further.

[00:23:07]So a caroxilic acid contains a caroxile group. So that's the spelling.

[00:23:12]Okay. And a caroxile group is a carbonile group attached to a hydroxy group. I said that already. You can see the examples there.

[00:23:23]Okay, now let's look at how do we name caroxilic acids.

[00:23:32]Again, like we've been doing previously, you find the longest chain here. Now that will have the caroxyic acid.

[00:23:43]Okay.

[00:23:46]Um, you would remove the last E like you've been doing and you add oic acid. Remove the last E, change it to oic acid. O, I space acid.

[00:24:02]That is basically it. So once you remember all the other rules we've been learning, finding the longest chain, uh giving substituent numbers in such a way that they take the lowest number possible, all those things, they all effective here.

[00:24:18]Okay. Now, carboids are terminal functional groups.

[00:24:24]What that means is that they usually sit at the end of the compound. So again, just like we did when we were talking about alihides for acids, you must choose the longest chain that contains the acid functionality.

[00:24:44]If the longest chain does not contain the acid functionality, you will ignore it. You will only choose the longest chain that has the acid functionality and every other thing will be a subsequent.

[00:24:57]And then when you number, you start numbering from the carbon that has the acid. So the CO that C that has the double bond oxygen and the O is the first carbon.

[00:25:14]Okay. So say for instance you have uh RC2 RC.

[00:25:25]Okay, this will be carbon one. This will be carbon 2 and so on and so forth.

[00:25:31]Okay, but there's a difference unlike all the other ones.

[00:25:36]The ones that you have carbonile.

[00:25:39]Now, if you were using uh Latin, I mean Greek numerals to to represent them.

[00:25:53]This carbon here that is carbon 2 when you are using numbers will be alpha. The next one will be beta. So if there's another carbon at here for instance to be carbon 3 but it will be beta because when you use alpha beta gamma all the rest you're talking about the next carbon that is connected to the functional group.

[00:26:17]Now I bring this to your attention because I want you to be able to differentiate this from say alcohol.

[00:26:24]Say if we were if we were to write this same compound with alcohol uh let me write alcohol say R CH2 O okay this is an alcohol in this case this will still be carbon one if there's a carbon atom here it will be carbon 2 okay but it will also be alpha beta So note the difference here. This carbon that is connected to the O is carbon one as well as alpha. Unlike here where the carbon that is on the functional group is one but the carbon that is connected to the functional group is two but alpha.

[00:27:17]I hope that's clear. If it's not, please consult Google.

[00:27:22]Okay, that's that's an aside. What is important in nomenclature so that if you go and if they name it and use the alpha beta and then you have to find you should be able to draw the structure and you will not be able to if you are confusing 1 2 3 with alpha beta gamma.

[00:27:43]Okay. So back to okay like I was saying so um the CO will be terminal you look for the longest chain.

[00:27:59]Okay but again like we had with the alihide the story changes if you have more than one caroxyic acid group.

[00:28:13]Okay, if you have more than one caroxilic acid group, then you must look for the longest chain that contains the two caroxilic groups. And in this case, it can be the case that the longest chain will be such a way that the caroxilic groups are substituents.

[00:28:42]Um let me give you an example what we call say CH2 CH2 C H2 C H C H C here C O H there.

[00:29:13]1 2 3 4 here. Let's put Let's put CH3 here.

[00:29:27]Okay. Now, look at this quickly.

[00:29:30]Um I know you can't see my ranty but here you have 1 2 3 4 5 or you can go here four five.

[00:29:45]You see this one is quite easy and I can assure you nobody will give you this easy one but assuming you see this okay you take this as a substitute in which case you're looking at five 5 n= 5 is p so you're going to have pentane diic acid and then this one will be 2 me okay um let's look at another For example, let's say here you have you have uh where's my you have CH now let me use the other you have C here you have O here O O C and then here you have CH3 three.

[00:30:48]Okay, now look at this. Um, so we're removing this.

[00:31:02]Uh, okay. So here now, if you're numbering, you can start with this.

[00:31:11]You do. Now there's one way. If you do 1 2 3 4 5 6.

[00:31:24]No, this is not a good example. But let me do this one first so that you'll see why it's not a good example shortly if you're paying attention.

[00:31:35]Or that six is straight.

[00:31:39]Or you can do because you want to factor in the acid do one 2 3 4 5 six.

[00:31:52]Okay.

[00:31:55]So this one now you're going to go with the acid obviously and then the two methile groups would be would be substituents.

[00:32:07]So you're going to have 2 five diameter hexen 16 diio acid.

[00:32:22]I'm just using this as an example. So if you're listening, you get it. If you're not, okay, but why did I say it's not a good example? Because obviously you can see. But the the point I wanted to make which I will do now is to put a CH2 here.

[00:32:45]Now note that I'm cleaning and giving everyone I do is a new compound.

[00:32:50]Okay? But I'm just to save time and space.

[00:32:56]So please don't confuse them. Don't think that uh in a test or in an exam you now start constructing your own compound. If they give you a compound that you don't like, you change it.

[00:33:07]If you if you change it and give your answer, the examiner will send you the script to mark and award yourself the score.

[00:33:16]Okay. So if we use this for instance now numbering the numbering the I think this one going to >> [clears throat] >> uh where is my numbering this.

[00:33:42]So this one will now be can go from here. 1 2 3 4 5 6.

[00:33:54]Let me correct this because I want to add to this one to help me make the point I'm making. So I've changed the question. Now I'm about to change the question. So here instead I want to have CH2 then another CH3 here. Okay? So that when I'm numbering I have 6 78. That's how I want to go. So the longest chain has eight carbon atoms.

[00:34:26]Okay.

[00:34:28]The chain that has the caroxilic acids has only six carbon atoms.

[00:34:36]Okay. So if you're doing the longest chain, okay, you should be going with the six carbon atom. I mean the eight carbon atoms.

[00:34:46]Okay. So now if you go with the eight carbon atoms, you are going to have n is equal to 8 is what?

[00:34:58]Octane. So this one you're going to have you can say you're going to call this obain 3 six. Follow me on so that you won't get lost. Octane 3 six because the two caroxilic acids are carbon 3 and six. So obtain space sorry hyphen 3 comma 6 hyphen di caroxilic acid or diioic acid.

[00:35:41]Okay, you can say that now if you say that you have used you have use the longest chain. Okay, but you have disobeyed the rule of caroxilic acid being terminal.

[00:36:00]But if you obey the rule of caroxilic acid being terminal, this you will now call 36 diile uh was uh was uh six again.

[00:36:27]4 six hexen you see now I've even forgotten so it will be 36 hexane 1 6 oh sorry 36 diile hexane hyphen 1 comma 6-phen diuric acid Okay, that one obeys the rules.

[00:37:01]Now, why I'm highlighting this for you is that to waste your time and to confuse you, the examiner might decide not to put that answer. Which answer am I talking about? Because you're doing multiple choice. The answer of 36 D itile assuming you were given this structure that I've drawn anyhow on this slide here.

[00:37:26]Assuming you are giving it and you asked to give the Iopath name, the examiner might intentionally leave out the correct answer of uh 36 dial hexen 16 diioic acid and then put the answer that is correct in the sense that you have two caroxilic acids there.

[00:37:58]Okay.

[00:38:00]So, if you if you use I don't want to cause more confusion for you, but what I want to say to you is sometimes as a gimmick to waste time.

[00:38:13]Your examiner can put a correct answer that will you you need to think twice to be able to choose it. Okay. Another gimmick is that the examiner can put two answers that are correct and then you expected to choose the more correct answer. Okay? Like if you were given this now you can have the two answers of uh 36 diile hexen one6 uh diic acid and you can also have the uh you can also have the the uh octane 16 diuric acid. Okay, both of them can be there.

[00:39:08]Now, the one that is more correct is the the one that is more correct is the 36 dial hexane 16 diuric acid.

[00:39:30]But the other one, the longer one is also correct in the sense that if you were to use the rule of longest chain and that even though caroxilica C is terminina sometimes it can be a substituent that answer will be correct but if you have the more correct one that's the one you must choose.

[00:39:53]I hope I haven't succeeded in confusing you. I'm just bringing your attention to something that you might not be aware of. By virtue of the kind of exam or test you're going to be doing, which is multiple choice, the examiner is allowed to play tricks on you to know whether you are paying attention or not.

[00:40:17]Anyway, so with that at the back of your mind, you should now be able to understand. I expect that you can look at these ones here and understand why this is metaninoic acid, propaninoic acid and then two propaninoic acid.

[00:40:33]If you cannot then it means that you haven't been listening to what I've been saying. In any case, you can come back next class with your question.

[00:40:42]Okay? So, I'm really sorry I have to rush. [sighs] But if you've been studying gradually, you'll be able to follow. In any case, many of these things like I mean you would have done a little bit of caroxilic acid in in jam to be able to enter the university.

[00:41:05]So this is more like to expand it or those of you that might have crammed to pass this is now your opportunity to understand it because it pays you better to understand than to cram. cramming you can forget and if you forget then that's big trouble. Okay. So uh here we said that the general formula for acid is RC.

[00:41:36]Okay. But in a solution it can ionize to give you RC minus plus H+.

[00:41:46]This is the exact reason why it is called an acid. Because if you remember from your secondary school definition, an acid is any compound that can generate a proton that can give out anion an ionizable hydrogen atom. Okay. The general So, so this here now is what you call the caroxilate ion. Okay.

[00:42:14]It's uh RC with excess electrons on one of the oxygen. The oxygen that would have been bonded to the hydrogen in the caroxilic acid.

[00:42:28]It now loses that it takes the electron the one electron very heartless thing.

[00:42:33]The one electron that hydrogen has the oxygen will take it away and leave it to go away empty-handed.

[00:42:40]So it will go away as H+ without any electron.

[00:42:43]while the oxygen will hold on to that electron. That oxygen when it holds onto that electron the whole entity is called a caroxilate.

[00:42:53]So that's what this is telling you and that is how this caroxilic acid compounds which are organic acids that's how they exhibit their acidity.

[00:43:06]Okay. So here this first one here you see an example of eaninoic acid that's the name the common name is acetic acid I'm sure most of you would have heard of acetic acid you see it in a lot of natural compounds it exists in nature that's why it's an organic acid anyway so you see there reacting with water because is in the presence of an achos medium. If there's no water that thing remains as it is there as the caroxilic acid does not ionize only ionizes in presence of water and then you can see what it forms.

[00:43:51]So that's a hydrononeium ion H3+ this you can also I'm sure some of you would have seen break down further into H+ plus H2O Okay. So that is the caroxilate for you and that is the characteristic of a caroxilic acid. All the other compounds you have learned I'm sure you can see none of them can do this.

[00:44:21]So whenever you see this you know that the caroxilic acid is in the house and then when it has lost the hydrogen it is a caroxilate.

[00:44:37]So naming caroxilic acid we've already done that. So if you look at all this you should be able to appreciate you see the e is removed and The oic acid is inserted. Again remember this is for IOPAC. Okay, this is for IOPAC.

[00:44:59]These rules common names do not obey them. As as we mentioned several times, common names originate from the source.

[00:45:08]Okay, you look at this now for instance uh metaninoic acid when C is equal to 1.

[00:45:16]Okay. But you can see that the common name is formic acid. Just like for alihide is formalihide.

[00:45:25]Okay.

[00:45:27]Ketone doesn't have that because ketone has to have at least at least three carbon atoms to be able to go anywhere.

[00:45:38]Okay. So then again you look at here that is eaninoanoic acidopac but you can see common is acetic acid.

[00:45:48]Can see there's no change or anything there. So that please [clears throat] don't confuse them. When you're dealing with common names the rules do not apply. It's only when you're dealing with pack.

[00:46:04]Okay. So you look at this the basic thing everything that you have learned remains the same apart from that you remove E and add O IC. So you can see the numbering you do it in such a way that it takes lowest and again you always start from the C that has the O H.

[00:46:26]Okay.

[00:46:30]Now some of you might not be used to this. So it's been brought to your attention. Look at this compound.

[00:46:38]Okay, you might look at it and first instance you just think it's an alcohol. It is intentional.

[00:46:46]If you don't look properly, you think that is an alcohol and then you go and name it as an alcohol because I can assure you the alcohol options will be there. You see maybe something like Dol.

[00:47:01]Okay. And if you choose that the computer will happily give you your odo.

[00:47:08]Do not make the computer happy to give you. So you look at it properly, you will see that this is what makes the difference. It has a carbon oxygen double bond there. Okay. And once you able to pick out that then you know that this is an acid.

[00:47:26]Okay. That just so the O will be a substituent. And you see you start numbering from the carbon that has the O I mean the carbon.

[00:47:35]So that's why this is five hydrox hexanoic acid because there are six carbon atoms there.

[00:47:51]This is too small for you. So if you start counting, you will see that this carbon here is the sixth one.

[00:48:01]Again, you've been taught that when you're using structures like this, once there's nothing at the end, once there's nothing at the end, if it's left like this, you automatically know that there's a CH3 there. Okay? If it isn't a CH3, it won't be left like this.

[00:48:23]it will have something on it like this one can see that there's O at the end there so that you know that there's O and I know you also know that wherever you see a vertex or a curve it is a CH2 there okay so sometimes you'll be given this kind of structures to test whether first of all you understand this shorthand way of writing chemical compounds So here now because you have things at the end of all these places whatever you have at the end that's what it is. But when you don't have things at the end you know that it's carbon and hydrogen then you check because carbon can only have four bonds. So here now if you take this one it has one bond here it has one bond here remaining two. So it's not shown but there's one H there one H there. And that is why those vertexes or those edges you have a CHQ. So if you bear that in mind and you check this you understand why this is hydroxy five hydroxy hexanoic acid. Then look at this one. This is aromatic. You see that obviously the naming is different.

[00:49:41]Okay. So you will take here because this is benzina is aromatic. The carbon atoms are equivalent.

[00:49:52]So you will start numbering from the alpha carbon. This is the alpha carbon here.

[00:50:01]Okay.

[00:50:03]But this numbering that you are seeing in red is not the numbering of the acido so that you don't get it mixed up. is the numbering of the benzene so that you can know. So in this case now you're cons you're taking the acid here as a substituent.

[00:50:21]Okay. So is a substituent on the benzene ring.

[00:50:27]So when you take the benzene you now want to know where the substituents are.

[00:50:34]And obviously the acid will take precedence over the amine.

[00:50:39]So that's why this. So now you take this whole compound as one.

[00:50:48]Okay, that's benzene. The acid takes precedence. So you take this as one.

[00:50:57]It's benzoic acid. Okay. Then this substr is here. What relationship is it?

[00:51:04]Since this one will always take number one because it's a functional group.

[00:51:09]What relationship does the amine or amino group have? That's where you should count. 1 2 3 4. So it is four amino. Amino is the substance. The remaining part, this first part that I've now covered in blue, that's the benzoic acid.

[00:51:34]We won't go too ind depth into this because this is just your first year. We don't want to scare you. Want you to come back in year two, year three, and year four and do more chemistry.

[00:51:49]Those of you who are chemistry students, you have no choice.

[00:51:53]You've already signed up. So, we're not afraid. You can't go anywhere.

[00:51:57]Is the other ones that want to recruit.

[00:52:00]Okay? So we will stop there for that so that you don't get scared.

[00:52:08]If you come back for more in year two we will entertain you.

[00:52:16]Okay. So now using that same you come across uh diix.

[00:52:27]You see now when you now have two caroxilic acid you put DI in front of the OIC to show that you have two caroxilic acids.

[00:52:37]Okay. And then in this case it is still the now instead of just removing E just one acid you remove E and you put O I but when it is two or more you leave everything as it is. A N E and you just put space and you put the diic. Usually you put space and put the number. So first of all, let me correct this. Those of you who are paying attention will see that there's a typographical error here. So please correct it. A T is missing here.

[00:53:15]Okay. So that's 18 diic. But again this next correction I want to make is that it is 10 hyphen 1 2 hyphen dioric okay that's the correct thing but I mean you have the fortune of having multiple choice so if you look at the options and you don't see this but you see this choose this one and go your way okay Remember you're choosing the most correct answer. So the same applies to this. If you count, you see that you have three carbon atoms there. That's why it's propane. N is equal up to three. And then there are two caroxilic acid functional. And again remember this is easy because the acids are at the end. Okay? I gave you example of where they're not at the end when I was using the long.

[00:54:17]Okay. So, first of all, I've explained the hard one and now I'm talking about the easy one should be uh they call it reverse psychology.

[00:54:28]So, if you didn't grab it then this is your opportunity to grab it now.

[00:54:33]So again here between the E between [clears throat] the E and the D you should have uh 1 comma 3 hyphen hyphen before you have the diic acid.

[00:54:49]So this is the benefit you get for attending class and not just collecting the slides from because you know the lecturer will give you slides collect it from whoever I don't I don't know what you'll be doing anyway rather than being in class because you've taken up the job of being a student.

[00:55:10]In any case you're also supposed to learn how to manage your time. So so the same thing applies. This is four. This is five.

[00:55:20]This is six. This one's the functional groups are terminal. So the longest chain is also in the same contains the acid.

[00:55:32]But where it doesn't contain it, you have seen the example.

[00:55:37]Okay. So we're going to stop there for today.

[00:55:41]On Wednesday, we look at the physical properties of caroxilic acids.

[00:55:46]Okay. So, let me see. Do we have any questions as we round up?

[00:55:53]No hand is raised. So, let's look at Q& A. No Q& A.

[00:56:02]Okay. So, I won't be going to the chat.

[00:56:04]You put a question there or your lower because your classmates have already filled it up with their their names even though I've told them there's no need. Okay. So have a lovely day.

[00:56:20]There will be no class on Monday sorry on Wednesday because the faculty of physical sciences or rather physical and earth sciences will be holding its annual lecture.

[00:56:36]You are all invited.

[00:56:39]Those of you who are in the faculty, it is compulsory that you attend.

[00:56:44]So the next our next meeting will be on